[llvm] [AMDGPU] Fix encoding of VOP3P dpp on GFX11 and GFX12 (PR #82710)

[Joe Nash via llvm-commits]

Sisyph wrote:

Nice job spotting it! I found an old email where I was confused about this exact topic, whether op_sel_hi should be set for these bits on this instruction, but never resolved it. Thanks.

https://github.com/llvm/llvm-project/pull/82710