net: ethernet: sunplus: add missing of_node_put() in spl2sw_mdio_init()

of_get_child_by_name() returns device node pointer with refcount
incremented. The refcount should be decremented before returning
from spl2sw_mdio_init().

Fixes: fd3040b9394c ("net: ethernet: Add driver for Sunplus SP7021")
Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Yang Yingliang <[e-mail]>
Reviewed-by: Wells Lu <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/sunplus/spl2sw_mdio.c

···
 
 	/* Allocate and register mdio bus. */
 	mii_bus = devm_mdiobus_alloc(&comm->pdev->dev);
-	if (!mii_bus)
-		return -ENOMEM;
+	if (!mii_bus) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
 	mii_bus->name = "sunplus_mii_bus";
 	mii_bus->parent = &comm->pdev->dev;
···
 	ret = of_mdiobus_register(mii_bus, mdio_np);
 	if (ret) {
 		dev_err(&comm->pdev->dev, "Failed to register mdiobus!\n");
-		return ret;
+		goto out;
 	}
 
 	comm->mii_bus = mii_bus;
+
+out:
+	of_node_put(mdio_np);
 	return ret;
 }