net: sparx5: fix return value check in sparx5_create_targets()

In case of error, the function devm_ioremap() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check should
be replaced with NULL test.

Fixes: 3cfa11ba ("net: sparx5: add the basic sparx5 driver")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/sparx5/sparx5_main.c

@@ -236,10 +236,10 @@ static int sparx5_create_targets(struct sparx5 *sparx5)
 					  iores[idx]->start,
 					  iores[idx]->end - iores[idx]->start
 					  + 1);
-		if (IS_ERR(iomem[idx])) {
+		if (!iomem[idx]) {
 			dev_err(sparx5->dev, "Unable to get switch registers: %s\n",
 				iores[idx]->name);
-			return PTR_ERR(iomem[idx]);
+			return -ENOMEM;
 		}
 		begin[idx] = iomem[idx] - sparx5_main_iomap[range_id[idx]].offset;
 	}