net: fec: add missing of_node_put() in fec_enet_init_stop_mode()

Put device node in error path in fec_enet_init_stop_mode().

Fixes: 8a448bf8 ("net: ethernet: fec: move GPR register offset and bit into DT")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220426125231.375688-1-yangyingliang@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/fec_main.c

@@ -3731,7 +3731,7 @@ static int fec_enet_init_stop_mode(struct fec_enet_private *fep,
 					 ARRAY_SIZE(out_val));
 	if (ret) {
 		dev_dbg(&fep->pdev->dev, "no stop mode property\n");
-		return ret;
+		goto out;
 	}
 
 	fep->stop_gpr.gpr = syscon_node_to_regmap(gpr_np);