[clang] [OpenMP][clang][HIP][CUDA] fix weak alias emit on device compilation (PR #164326)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 commented:

Style nits

@Artem-B CUDA does not support weak on anything but non-kernel functions. Should we handle that in Sema or just let the backend die later.

https://github.com/llvm/llvm-project/pull/164326