net: dsa: felix: check return code of mdio_alloc and mdio_register

These functions can return errors, it's best to catch them and trigger
the driver unwind code path.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/drivers/net/mscc_eswitch/felix_switch.c b/drivers/net/mscc_eswitch/felix_switch.c
index 711dd44..551fc2c 100644
--- a/drivers/net/mscc_eswitch/felix_switch.c
+++ b/drivers/net/mscc_eswitch/felix_switch.c
@@ -275,6 +275,7 @@
 static int felix_probe(struct udevice *dev)
 {
 	struct felix_priv *priv = dev_get_priv(dev);
+	int err;
 
 	if (ofnode_valid(dev_ofnode(dev)) &&
 	    !ofnode_is_available(dev_ofnode(dev))) {
@@ -299,11 +300,18 @@
 		struct mii_dev *mii_bus;
 
 		mii_bus = mdio_alloc();
+		if (!mii_bus)
+			return -ENOMEM;
+
 		mii_bus->read = felix_mdio_read;
 		mii_bus->write = felix_mdio_write;
 		mii_bus->priv = priv->imdio_base + FELIX_PM_IMDIO_BASE;
 		strlcpy(mii_bus->name, dev->name, MDIO_NAME_LEN);
-		mdio_register(mii_bus);
+		err = mdio_register(mii_bus);
+		if (err) {
+			mdio_free(mii_bus);
+			return err;
+		}
 	}
 
 	dm_pci_clrset_config16(dev, PCI_COMMAND, 0, PCI_COMMAND_MEMORY);