[llvm] [AMDGPU] Enable copy from VCC to SHARED_BASE. (PR #164138)

[Shilei Tian via llvm-commits]

https://github.com/shiltian requested changes to this pull request.

I don't think `s_mov_b64` would allow `SRC_SHARED_BASE` as destination register. It is not one of the categories in `sdst`.

https://github.com/llvm/llvm-project/pull/164138