Remove some remants of the old palign pattern fragment that were still hanging around...

Remove some remants of the old palign pattern fragment that were still hanging around. Also remove a cast from inside getShuffleVPERM2X128Immediate and getShuffleVPERMILPImmediate since the only caller already had done the cast.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146344 91177308-0d34-0410-b5e6-96231b3b80d8