[clang] [llvm] [AMDGPU] Guard more intrinsics with target features (PR #203956)

[Krzysztof Drewniak via cfe-commits]

https://github.com/krzysz00 approved this pull request.

No objection as to the contents, but we should probably spin up that RFC

https://github.com/llvm/llvm-project/pull/203956