[llvm] [PowerPC] clean unused PPC target feature FeatureBPERMD (PR #159782)

[Sergei Barannikov via llvm-commits]

s-barannikov wrote:

> I'm not sure I understand why the CI passed on this PR

Or did it not? The checks were red and became green after updating a branch, but the merge update didn't trigger all checks


https://github.com/llvm/llvm-project/pull/159782