Remove more dead LR-as-GPR PPC code

I had removed similar code a few days ago, but somehow missed this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178169 91177308-0d34-0410-b5e6-96231b3b80d8
Fix typo (common to both X86 and PPC)

Thanks to Bill Schmidt for pointing this out during code review!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178170 91177308-0d34-0410-b5e6-96231b3b80d8