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

[Zarko Todorovski via cfe-commits]

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

LGTM, with the comments above. It would be good to get a different set of eyes to have a look if possible. 

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