Revert "[X86][AMX] Support AMX-AVX512" (#115570)
Reverts llvm/llvm-project#114070
Reason: Causes `immintrin.h` to fail to compile if `-msse` and
`-mno-sse2` are passed to clang:
https://github.com/llvm/llvm-project/pull/114070#issuecomment-2465926700
