[llvm] [AMDGPU] Add an asm directive to track code_object_version (PR #76267)

[Emma Pilkington via llvm-commits]

epilk wrote:

@slinder1 @arsenm Ah, so code_object_version is only meaningful on HSA OSes? I originally chose 'amdgcn' since I thought it was also meaningful on PAL/Mesa. The update renames the directive to `amdhsa_code_object_version` and only emits/parses it on HSA triples.

I noticed that clang emits the IR module flag, `amdgpu_code_object_verison` on PAL/mesa. Should that be updated to just emit on HSA? Thanks!

https://github.com/llvm/llvm-project/pull/76267