[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 `premerge-monolithic-linux` running on `premerge-linux-1` while building `llvm` at step 6 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/153/builds/29561

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

```
Step 6 (build-unified-tree) failure: build (failure)
...
4.656 [4012/12/105] Linking CXX executable bin/clang-reorder-fields
4.680 [4012/11/106] Linking CXX executable bin/tool-template
4.682 [4012/10/107] Linking CXX executable bin/clang-refactor
4.683 [4012/9/108] Linking CXX executable bin/clang-installapi
4.724 [4012/8/109] Linking CXX executable bin/clang-query
5.112 [4012/7/110] Linking CXX executable bin/clangd-indexer
5.214 [4012/6/111] Linking CXX executable bin/clangd-fuzzer
5.269 [4012/5/112] Linking CXX executable bin/clangd
5.366 [4012/4/113] Linking CXX executable bin/clang-tidy
7.465 [4012/3/114] Building CXX object lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o
FAILED: lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /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/build/buildbot/premerge-monolithic-linux/build/lib/Target/RISCV -I/build/buildbot/premerge-monolithic-linux/llvm-project/llvm/lib/Target/RISCV -I/build/buildbot/premerge-monolithic-linux/build/include -I/build/buildbot/premerge-monolithic-linux/llvm-project/llvm/include -gmlt -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 /build/buildbot/premerge-monolithic-linux/llvm-project/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
/build/buildbot/premerge-monolithic-linux/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);
          ^~~~~~~~~~~~~~~~~~~~~~~
/build/buildbot/premerge-monolithic-linux/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.
12.082 [4012/2/115] Building CXX object lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/AsmPrinter.cpp.o
13.433 [4012/1/116] 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