[X86] Remove superfluous trailing semicolons, fixing warnings. NFC.

Author: mstorsjo

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -35730,8 +35730,8 @@ namespace llvm {
     enum {
       MaxShuffleCombineDepth = 8
     };
-  };
-}; // namespace llvm
+  }
+} // namespace llvm
 
 /// Fully generic combining of x86 shuffle instructions.
 ///