net: moxa: fix an error code

We accidentally return IS_ERR(priv->base) which is 1 instead of
PTR_ERR(priv->base) which is the error code.

Fixes: 6c821bd9edc9 ('net: Add MOXA ART SoCs ethernet driver')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/moxa/moxart_ether.c

@@ -474,9 +474,9 @@ static int moxart_mac_probe(struct platform_device *pdev)
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	ndev->base_addr = res->start;
 	priv->base = devm_ioremap_resource(p_dev, res);
-	ret = IS_ERR(priv->base);
-	if (ret) {
+	if (IS_ERR(priv->base)) {
 		dev_err(p_dev, "devm_ioremap_resource failed\n");
+		ret = PTR_ERR(priv->base);
 		goto init_fail;
 	}