[X86] Change some patterns that select MOVZX16rm8 to instead select MOVZX32rm8 and extract the subregister.

This should be a shorter encoding and is consistent with what we do for zext i8->i16

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@350988 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed