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

[Stanislav Mekhanoshin via llvm-commits]

rampitec wrote:

Then the root of the problem is that VOP3P had no DPP when the code was written, so GFX9 code is OK and e64 encoding is correct. Then it was not properly verified when DPP support was added in GFX11.

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