[clang] [llvm] [AMDGPU] Introduce asyncmark/wait intrinsics (PR #173259)

[Krzysztof Drewniak via llvm-commits]

https://github.com/krzysz00 commented:

Also, AMDGPULowerBufferFatPointers should be updated for the new load.to.lds intrinsic

https://github.com/llvm/llvm-project/pull/173259