[X86] Add missing override. NFC.

llvm-svn: 316299
diff --git a/llvm/lib/Target/X86/X86Subtarget.h b/llvm/lib/Target/X86/X86Subtarget.h
index 133fa01..a8d7f29 100644
--- a/llvm/lib/Target/X86/X86Subtarget.h
+++ b/llvm/lib/Target/X86/X86Subtarget.h
@@ -673,9 +673,7 @@
     return TargetSubtargetInfo::ANTIDEP_CRITICAL;
   }
 
-  virtual bool enableAdvancedRASplitCost() const {
-    return true;
-  }
+  bool enableAdvancedRASplitCost() const override { return true; }
 };
 
 } // end namespace llvm