[clang] [Clang] Enable hip_atomic deprecation warning by default (PR #230378)

[Sameer Sahasrabuddhe via cfe-commits]

ssahasra wrote:

I added a few reviewers, but do add more from the history of these builtins ... anyone who had an opinion.

Please ensure that this PR gets wide exposure. Presumably, this will be committed only after we have scrubbed all uses that are under our control? Also reach out to known external users wherever possible.

https://github.com/llvm/llvm-project/pull/230378