Unfortunately several files in MC are badly violating layering rule by using

Unfortunately several files in MC are badly violating layering rule by using
TargetAsmInfo, which in turn pulls in TargetRegisterInfo, etc. :-( There are
other cases of violations, but this is probably the worst.

This patch is but one small step towards fixing this. 500 more steps to go. :-(

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135131 91177308-0d34-0410-b5e6-96231b3b80d8