Do not use templates to instantiate {Object,Shared}Files.

createELFFile looked complex because of its use of template,
so I want to keep it private within this file.

llvm-svn: 256880
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
index f8d5852..4af1b88 100644
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -115,8 +115,7 @@
   // read from the library.
   if (MBRef.getBuffer().empty())
     return std::unique_ptr<InputFile>(nullptr);
-
-  return createELFFile<ObjectFile>(MBRef);
+  return createObjectFile(MBRef);
 }
 
 template <class ELFT> static void doInitSymbols() {