[clang] [llvm] [x86][AVX-VNNI] Fix VPDPWXXD Argument Types (PR #169456)

[Phoebe Wang via llvm-commits]

https://github.com/phoebewang approved this pull request.

X86 changes LG, just 2 minors and one question for MemorySanitizer.

https://github.com/llvm/llvm-project/pull/169456