Transforms: address some late comments

We already use the llvm namespace.  Remove the unnecessary prefix.  Use the
StringRef::equals method to compare with C strings rather than instantiating
std::strings.

Addresses late review comments from David Majnemer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221564 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed