Remove dead code.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@216152 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF] Don't use default argument.

I'm adding new parameters to the function, and the existing
parameter with a default argument is found confusing.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@216153 91177308-0d34-0410-b5e6-96231b3b80d8