Update debug message wording

Co-authored-by: Abhishek Varma <[email protected]>

Author: krzysz00

mlir/lib/Dialect/Affine/IR/AffineOps.cpp

@@ -4788,7 +4788,7 @@ struct SplitDelinearizeSpanningLastLinearizeArg final
 
     if (elemsToSplit < 2)
       return rewriter.notifyMatchFailure(
-          delinearizeOp, "don't have a non-trivial basis product");
+          delinearizeOp, "need at least two elements to form the basis product");
 
     Value linearizeWithoutBack =
         rewriter.create<affine::AffineLinearizeIndexOp>(