[llvm] [PowerPC] move the `PowerPC VSX FMA Mutation pass` head of `Register Coalescer pass` for option `-schedule-ppc-vsx-fma-mutation-early` (PR #111696)

[Lei Huang via llvm-commits]

lei137 wrote:

The description for this PR is way too long to be used as a commit message.  I think it's better if you put the details in the issue this PR fixes (open one if there isn't one) and provide a more general commit message here.

https://github.com/llvm/llvm-project/pull/111696