[llvm] [NFC][MC] Removed unused switch case in `emitCATTR` (PR #152907)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `sanitizer-x86_64-linux-android` running on `sanitizer-buildbot-android` while building `llvm` at step 2 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/186/builds/11470

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 2 (annotate) failure: 'python ../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py' (failure)
...
[1948/5580] Building CXX object lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyldMachO.cpp.o
[1949/5580] Building CXX object lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/Targets/RuntimeDyldELFMips.cpp.o
[1950/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/RegisterTargetPassConfigCallback.cpp.o
[1951/5580] Building CXX object lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyldELF.cpp.o
[1952/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/Target.cpp.o
[1953/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/TargetLoweringObjectFile.cpp.o
[1954/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/TargetMachine.cpp.o
[1955/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/TargetMachineC.cpp.o
[1956/5580] Building AArch64GenDAGISel.inc...
[1957/5580] Building CXX object lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o
FAILED: lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes CCACHE_SLOPPINESS=pch_defines,time_macros /usr/bin/ccache /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build0/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/lib/MC -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/MC -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/include -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o -MF lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o.d -o lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o -c /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/MC/MCAsmInfoGOFF.cpp
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/MC/MCAsmInfoGOFF.cpp:64:13: error: enumeration value 'ESD_RMODE_None' not handled in switch [-Werror,-Wswitch]
   64 |     switch (Rmode) {
      |             ^~~~~
1 error generated.
[1958/5580] Building AArch64GenInstrInfo.inc...
[1959/5580] Building CXX object lib/MC/MCParser/CMakeFiles/LLVMMCParser.dir/AsmParser.cpp.o
[1960/5580] Building AArch64GenSubtargetInfo.inc...
[1961/5580] Building AMDGPUGenPostLegalizeGICombiner.inc...
[1962/5580] Building AMDGPUGenMCPseudoLowering.inc...
[1963/5580] Building AMDGPUGenMCCodeEmitter.inc...
[1964/5580] Building AMDGPUGenDisassemblerTables.inc...
[1965/5580] Building AMDGPUGenCallingConv.inc...
[1966/5580] Building AMDGPUGenAsmWriter.inc...
[1967/5580] Building AMDGPUGenAsmMatcher.inc...
[1968/5580] Building AMDGPUGenInstrInfo.inc...
[1969/5580] Building AMDGPUGenGlobalISel.inc...
[1970/5580] Building AMDGPUGenDAGISel.inc...
ninja: build stopped: subcommand failed.

How to reproduce locally: https://github.com/google/sanitizers/wiki/SanitizerBotReproduceBuild


@@@STEP_FAILURE@@@

@@@STEP_FAILURE@@@

@@@STEP_FAILURE@@@
Step 8 (bootstrap clang) failure: bootstrap clang (failure)
...
[1948/5580] Building CXX object lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyldMachO.cpp.o
[1949/5580] Building CXX object lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/Targets/RuntimeDyldELFMips.cpp.o
[1950/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/RegisterTargetPassConfigCallback.cpp.o
[1951/5580] Building CXX object lib/ExecutionEngine/RuntimeDyld/CMakeFiles/LLVMRuntimeDyld.dir/RuntimeDyldELF.cpp.o
[1952/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/Target.cpp.o
[1953/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/TargetLoweringObjectFile.cpp.o
[1954/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/TargetMachine.cpp.o
[1955/5580] Building CXX object lib/Target/CMakeFiles/LLVMTarget.dir/TargetMachineC.cpp.o
[1956/5580] Building AArch64GenDAGISel.inc...
[1957/5580] Building CXX object lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o
FAILED: lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes CCACHE_SLOPPINESS=pch_defines,time_macros /usr/bin/ccache /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build0/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/lib/MC -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/MC -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/include -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o -MF lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o.d -o lib/MC/CMakeFiles/LLVMMC.dir/MCAsmInfoGOFF.cpp.o -c /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/MC/MCAsmInfoGOFF.cpp
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/MC/MCAsmInfoGOFF.cpp:64:13: error: enumeration value 'ESD_RMODE_None' not handled in switch [-Werror,-Wswitch]
   64 |     switch (Rmode) {
      |             ^~~~~
1 error generated.
[1958/5580] Building AArch64GenInstrInfo.inc...
[1959/5580] Building CXX object lib/MC/MCParser/CMakeFiles/LLVMMCParser.dir/AsmParser.cpp.o
[1960/5580] Building AArch64GenSubtargetInfo.inc...
[1961/5580] Building AMDGPUGenPostLegalizeGICombiner.inc...
[1962/5580] Building AMDGPUGenMCPseudoLowering.inc...
[1963/5580] Building AMDGPUGenMCCodeEmitter.inc...
[1964/5580] Building AMDGPUGenDisassemblerTables.inc...
[1965/5580] Building AMDGPUGenCallingConv.inc...
[1966/5580] Building AMDGPUGenAsmWriter.inc...
[1967/5580] Building AMDGPUGenAsmMatcher.inc...
[1968/5580] Building AMDGPUGenInstrInfo.inc...
[1969/5580] Building AMDGPUGenGlobalISel.inc...
[1970/5580] Building AMDGPUGenDAGISel.inc...
ninja: build stopped: subcommand failed.

How to reproduce locally: https://github.com/google/sanitizers/wiki/SanitizerBotReproduceBuild




program finished with exit code 2
elapsedTime=94.796607

```

</details>

https://github.com/llvm/llvm-project/pull/152907