[Asm] Fix another layering violation in assmebly macro dumping

AsmToken is in the MCParser library, so we can't use its dump function from
MCAsmMacro in the MC library. Instead, just print the string, which we don't
need the MCParser library for.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@326810 91177308-0d34-0410-b5e6-96231b3b80d8