[clang] [Clang][HIP] Warn when __AMDGCN_WAVEFRONT_SIZE is used in host code (PR #91478)

[Alex Voicu via cfe-commits]

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

This looks fine to me (I do hate that macro being defined on the host though, so I am biased). Thanks!

https://github.com/llvm/llvm-project/pull/91478