[PowerPC] Support "eieio" instruction

This adds support for the "eieio" instruction to
the asm parser.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185349 91177308-0d34-0410-b5e6-96231b3b80d8

[PowerPC] Add "wait" instruction

This adds the "wait" instruction and its extended mnemonics.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185350 91177308-0d34-0410-b5e6-96231b3b80d8