[llvm] [AMDGPU] Fix to prevent sinking of PERMLANE_SWAP instruction (PR #144423)

[Vigneshwar Jayakumar via llvm-commits]

VigneshwarJ wrote:

@jayfoad, Should I merge this and create a new PR for the other PERMLANE instructions you mentioned?

https://github.com/llvm/llvm-project/pull/144423