[mlir][memref] Fix build after #132545 (#133760)

There was a typo in the error message.
diff --git a/mlir/lib/Dialect/MemRef/Transforms/RuntimeOpVerification.cpp b/mlir/lib/Dialect/MemRef/Transforms/RuntimeOpVerification.cpp
index 4537977..cd920265 100644
--- a/mlir/lib/Dialect/MemRef/Transforms/RuntimeOpVerification.cpp
+++ b/mlir/lib/Dialect/MemRef/Transforms/RuntimeOpVerification.cpp
@@ -370,7 +370,7 @@
       builder.create<cf::AssertOp>(
           loc, lastPosInBounds,
           RuntimeVerifiableOpInterface::generateErrorMessage(
-              op, "Subview runs out-of-bounds along dimension" +
+              op, "subview runs out-of-bounds along dimension " +
                       std::to_string(i)));
     }
   }