[X86] Limit the 'x' inline assembly constraint to zmm0-15 when used for a 512 type.

The 'v' constraint is used to select zmm0-31. This makes 512 bit consistent with 128/256-bit.a

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358450 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed