net: mscc: ocelot: Add of_node_put() before goto

Fix following coccicheck warning:
./drivers/net/ethernet/mscc/ocelot_vsc7514.c:946:1-33: WARNING: Function
for_each_available_child_of_node should have of_node_put() before goto.

Early exits from for_each_available_child_of_node should decrement the
node reference counter.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mscc/ocelot_vsc7514.c

@@ -969,6 +969,7 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
 		target = ocelot_regmap_init(ocelot, res);
 		if (IS_ERR(target)) {
 			err = PTR_ERR(target);
+			of_node_put(portnp);
 			goto out_teardown;
 		}