[clang] [llvm] [OpenMP] Add amdgpu-num-work-groups attribute to OpenMP kernels (PR #87695)

[Matt Arsenault via cfe-commits]

arsenm wrote:

Note this attribute doesn't actually do anything yet. @jwanggit86 are you working on implementing the propagation and optimizations with this?

https://github.com/llvm/llvm-project/pull/87695