Simplify x86 disassembler table handling of when to use TYPE_Rv/TYPE_R16/TYPE_R32 now that HasOpSizePrefix only means 16-bit instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199295 91177308-0d34-0410-b5e6-96231b3b80d8