net: dsa: Utilize dsa_slave_dev_check()

Instead of open coding the check.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/slave.c

@@ -1294,7 +1294,7 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb,
 {
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 
-	if (dev->netdev_ops != &dsa_slave_netdev_ops)
+	if (!dsa_slave_dev_check(dev))
 		return NOTIFY_DONE;
 
 	if (event == NETDEV_CHANGEUPPER)