[llvm] [AMDGPU] Remove unnecessary conditionality on atomic CSUB pseudo-ops (PR #69914)

[Jay Foad via llvm-commits]

https://github.com/jayfoad approved this pull request.

Looks OK to me, though I don't understand why setting OtherPredicates on the Pseudo did not get copied to the corresponding Real instructions and prevent them from being assembled/disassembled.

https://github.com/llvm/llvm-project/pull/69914