Remove unnecessary classof()'s

isa<> et al. automatically infer when the cast is an upcast (including a
self-cast), so these are no longer necessary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165767 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Object/COFF.h

@@ -198,7 +198,6 @@ public:
   static inline bool classof(const Binary *v) {
     return v->isCOFF();
   }
-  static inline bool classof(const COFFObjectFile *v) { return true; }
 };
 
 }