net: mdio-ipq4019: add missing error check

If an optional resource is found but fails to remap, return on failure.
Avoids any potential problems when using the iomapped resource as the
assumption is that it's available.

Fixes: 23a890d ("net: mdio: Add the reset function for IPQ MDIO driver")
Signed-off-by: Rosen Penev <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

Author: neheb

drivers/net/mdio/mdio-ipq4019.c

@@ -352,8 +352,11 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
 	/* The platform resource is provided on the chipset IPQ5018 */
 	/* This resource is optional */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-	if (res)
+	if (res) {
 		priv->eth_ldo_rdy = devm_ioremap_resource(&pdev->dev, res);
+		if (IS_ERR(priv->eth_ldo_rdy))
+			return PTR_ERR(priv->eth_ldo_rdy);
+	}
 
 	bus->name = "ipq4019_mdio";
 	bus->read = ipq4019_mdio_read_c22;