[llvm] [AMDGPU] Allow buffer intrinsics to be marked volatile at the IR level (PR #77847)

[Piotr Sobczak via llvm-commits]

piotrAMD wrote:

> I think this lgtm, but where did the patch for the fat buffer lowering go? I can't seem to find it

https://reviews.llvm.org/D158463

https://github.com/llvm/llvm-project/pull/77847