[llvm] [AMDGPU] Relax SOPK immediate signed/unsigned check (PR #77015)

[Stanislav Mekhanoshin via llvm-commits]

rampitec wrote:

> You can use an SDNodeXForm on the immediate to fix it up during selection

https://github.com/llvm/llvm-project/pull/77997

https://github.com/llvm/llvm-project/pull/77015