[Mips] Unify #include guard names.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@200715 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] In case of executable file linking MIPS ABI requires to add even
undefined symbols to '.dynsym' if these symbols have corresponding entries
in a global part of GOT.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@200716 91177308-0d34-0410-b5e6-96231b3b80d8