[llvm] [AMDGPU] Split vgpr regalloc pipeline (PR #93526)

[Christudasan Devadasan via llvm-commits]

cdevadas wrote:

> Can this finally land after [735a5f6](https://github.com/llvm/llvm-project/commit/735a5f67e351fc072a9f7c18b030036681f7935a)?

Yes. Will be landing in a few minutes.

https://github.com/llvm/llvm-project/pull/93526