[llvm] [AMDGPU] Do not treat LDSDMA as VALU in several passes (PR #212866)

[Akash Dutta via llvm-commits]

akadutta wrote:

@jayfoad that's what I understood from the issue and Jeff's older PR as well.
@arsenm @Pierre-vh if we should take a different route, I'd be happy to discuss and work on that.

https://github.com/llvm/llvm-project/pull/212866