[X86] Allow assembly parser to accept x/y/z suffixes on non-memory...

[X86] Allow assembly parser to accept x/y/z suffixes on non-memory vfpclassps/pd and on memory forms in intel syntax

The x/y/z suffix is needed to disambiguate the memory form in at&t syntax since no xmm/ymm/zmm register is mentioned.

But we should also allow it for the register and broadcast forms where its not needed for consistency. This matches gas.

The printing code will still only use the suffix for the memory form where it is needed.

llvm-svn: 359903