[llvm] [RISCV][TTI] Use processShuffleMask for shuffle legalization estimate (PR #136191)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-x86_64-debian` running on `lldb-x86_64-debian` while building `llvm` at step 4 "build".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/162/builds/20721

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

```
Step 4 (build) failure: build (failure)
...
4.582 [51/12/73] Linking CXX executable bin/llvm-extract
4.728 [51/11/74] Linking CXX executable bin/llvm-jitlink
4.998 [51/10/75] Linking CXX executable bin/diagtool
5.019 [51/9/76] Linking CXX shared module lib/CheckerOptionHandlingAnalyzerPlugin.so
5.020 [51/8/77] Linking CXX shared module lib/CheckerDependencyHandlingAnalyzerPlugin.so
5.023 [51/7/78] Linking CXX shared module lib/SampleAnalyzerPlugin.so
5.285 [51/6/79] Linking CXX executable bin/clang-diff
5.365 [51/5/80] Linking CXX executable bin/clang-installapi
5.389 [51/4/81] Linking CXX executable bin/clang-refactor
7.005 [51/3/82] Building CXX object lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o
FAILED: lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o 
/usr/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/home/worker/2.0.1/lldb-x86_64-debian/build/lib/Target/RISCV -I/home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/lib/Target/RISCV -I/home/worker/2.0.1/lldb-x86_64-debian/build/include -I/home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -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 -fvisibility=hidden  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o -MF lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o.d -o lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o -c /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
/home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp:710:11: error: no matching function for call to 'costShuffleViaSplitting'
          costShuffleViaSplitting(*this, LT.second, FVTp, Mask, CostKind);
          ^~~~~~~~~~~~~~~~~~~~~~~
/home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp:392:24: note: candidate function not viable: 1st argument ('const llvm::RISCVTTIImpl') would lose const qualifier
static InstructionCost costShuffleViaSplitting(RISCVTTIImpl &TTI, MVT LegalVT,
                       ^
1 error generated.
11.293 [51/2/83] Building CXX object lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/AsmPrinter.cpp.o
12.389 [51/1/84] Building CXX object lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/136191