[llvm] [MIPS] Fix the opcode of max.fmt and mina.fmt and make them matchable by ISel (PR #85609)

[Cinhi Young via llvm-commits]

Cyanoxygen wrote:

> I think that we should split it to 2 commits.

Sure! But would it be better if we split this into two PRs? I've now removed unrelated changes from this branch. 

https://github.com/llvm/llvm-project/pull/85609