[llvm] [AMDGPU] Let SIOptimizeVGPRLiveRange handle AV-class virtual registers (PR #226527)

[Krzysztof Drewniak via llvm-commits]

https://github.com/krzysz00 approved this pull request.

Seems fine to me, but I wonder if this has end-to-end effect on something / why we're doing it.

https://github.com/llvm/llvm-project/pull/226527