[llvm] [AMDGPU] misched: avoid subregister dependencies (PR #140255)

[Robert Imschweiler via llvm-commits]

ro-i wrote:

I feel like there might be a conflict with https://github.com/llvm/llvm-project/commit/c256966fe2129ef75c76a4cab454b35ffa9410f3#diff-542d3e260c6e545f29ad24eb096fcfb90a0b6a4cbc08e613971c26451098c1fb. Needs further investigation.

https://github.com/llvm/llvm-project/pull/140255