DwarfDebug: Unconditionalize trivial asm comments

While we still have a few (~4) non-trivial comments with string
concatenation, etc that should remain conditionalized, these trivial
literal comments can be simplified.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196416 91177308-0d34-0410-b5e6-96231b3b80d8