[clang] [FMV][AIX] Implement target_clones (cpu-only) (PR #177428)

[Zarko Todorovski via cfe-commits]

ZarkoT wrote:

Forgot to add that we will need to update the clang docs: https://clang.llvm.org/docs/AttributeReference.html#target-clones

https://github.com/llvm/llvm-project/pull/177428