[llvm] [AMDGPU] Add target feature require-naturally-aligned-buffer-access (PR #115479)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

This needs codegen tests. I would expect this to touch addressing mode matching. I don't believe this is sufficient for correct handling, and will only partially avoid introducing new violations 

https://github.com/llvm/llvm-project/pull/115479