[mlir] Fix a warning

This patch fixes:

  mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp:202:2:
  error: extra ';' outside of a function is incompatible with C++98
  [-Werror,-Wc++98-compat-extra-semi]

Author: kazutakahirata

mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp

@@ -199,7 +199,7 @@ emulatedVectorLoad(OpBuilder &rewriter, Location loc, Value base,
   return rewriter.create<vector::BitCastOp>(
       loc, VectorType::get(numEmultedElementsToLoad * scale, origElemType),
       newLoad);
-};
+}
 
 namespace {