[llvm] [AMDGPU] Skip register uses in AMDGPUResourceUsageAnalysis (PR #133242)

[Diana Picus via llvm-commits]

https://github.com/rovka commented:

I made some pretty large changes:
* Unified handling of leaf and non-leaf functions as much as possible.
* Added any used preloaded SGPRs to the SGPR count (since they'll be written by the hardware)

https://github.com/llvm/llvm-project/pull/133242