IB/mlx4: Check correct variable for allocation failure

The intent here is to check the "mfrpl->mapped_page_list" allocation.
We checked "mfrpl->ibfrpl.page_list" earlier.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mlx4/mr.c

@@ -238,7 +238,7 @@ struct ib_fast_reg_page_list *mlx4_ib_alloc_fast_reg_page_list(struct ib_device
 	mfrpl->mapped_page_list = dma_alloc_coherent(&dev->dev->pdev->dev,
 						     size, &mfrpl->map,
 						     GFP_KERNEL);
-	if (!mfrpl->ibfrpl.page_list)
+	if (!mfrpl->mapped_page_list)
 		goto err_free;
 
 	WARN_ON(mfrpl->map & 0x3f);