net: pass info struct via netdevice notifier

So far, only net_device * could be passed along with netdevice notifier
event. This patch provides a possibility to pass custom structure
able to provide info that event listener needs to know.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>

v2->v3: fix typo on simeth
	shortened dev_getter
	shortened notifier_info struct name
v1->v2: fix notifier_call parameter in call_netdevice_notifier()
Signed-off-by: David S. Miller <davem@davemloft.net>

net/x25/af_x25.c

@@ -224,7 +224,7 @@ static void x25_kill_by_device(struct net_device *dev)
 static int x25_device_event(struct notifier_block *this, unsigned long event,
 			    void *ptr)
 {
-	struct net_device *dev = ptr;
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct x25_neigh *nb;
 
 	if (!net_eq(dev_net(dev), &init_net))