[llvm] [AMDGPU][True16][CodeGen] update wwm reg sorting check condition (PR #135053)

[Brox Chen via llvm-commits]

broxigarchen wrote:

> > > Please add a test
> > 
> > 
> > I checked the wwm reg related test and it seems I could not find any thing that test for the sorting of the reserved reg. Hi @cdevadas are you comfortable with merging this as it, or is there a recommended test that I can look into? Thanks for the hint!
> 
> This change you added to skip the 16-bit wwm-regs. Did you happen to encounter any errors earlier? If yes, add a test for the 16-bit register - nothing to be added for the 32-bit wwm-reg case.

Added a test. I am not quite familar with wwm reg so please let me know if the test seems wrong to you. Thanks!

https://github.com/llvm/llvm-project/pull/135053