[llvm] powerpc: recognize `vmnsub` in older ppc versions (PR #155465)

[Folkert de Vries via llvm-commits]

folkertdev wrote:

I'm still not entirely sure of the LLVM review process, I'm guessing we're waiting for a second approval? In any case, I cannot merge this PR, someone else will have to do that.

https://github.com/llvm/llvm-project/pull/155465