[llvm] [AMDGPU] Add post-RA peephole to fuse v_lshlrev_b32 + v_or_b32 into v_lshl_or_b32 (PR #202585)

[Barbara Mitic via llvm-commits]

https://github.com/barbara-amd edited https://github.com/llvm/llvm-project/pull/202585