[C++11] Add 'override' keywords and remove 'virtual'. Additionally add 'final' and leave 'virtual' on some methods that are marked virtual without overriding anything and have no obvious overrides themselves. XCore edition

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207501 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/XCore/XCoreTargetMachine.cpp

@@ -46,9 +46,9 @@ public:
     return getTM<XCoreTargetMachine>();
   }
 
-  virtual bool addPreISel();
-  virtual bool addInstSelector();
-  virtual bool addPreEmitPass();
+  bool addPreISel() override;
+  bool addInstSelector() override;
+  bool addPreEmitPass() override;
 };
 } // namespace