Tag x86 move to/from debug/control registers with Not64BitMode/In64BitMode. Remove disassembler hack.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198515 91177308-0d34-0410-b5e6-96231b3b80d8
Add missed cleanup from r198456

All other uses of this macro in LLVM/clang have been moved to the function
definition so follow suite (and the usage advice) here too for consistency.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198516 91177308-0d34-0410-b5e6-96231b3b80d8