[ATALK]: In notifier handlers convert the void pointer to a netdevice

This slightly improves code safety and clarity.

Later network namespace patches touch this code so this is a
preliminary cleanup.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/appletalk/aarp.c

@@ -330,15 +330,16 @@ static void aarp_expire_timeout(unsigned long unused)
 static int aarp_device_event(struct notifier_block *this, unsigned long event,
 			     void *ptr)
 {
+	struct net_device *dev = ptr;
 	int ct;
 
 	if (event == NETDEV_DOWN) {
 		write_lock_bh(&aarp_lock);
 
 		for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
-			__aarp_expire_device(&resolved[ct], ptr);
-			__aarp_expire_device(&unresolved[ct], ptr);
-			__aarp_expire_device(&proxies[ct], ptr);
+			__aarp_expire_device(&resolved[ct], dev);
+			__aarp_expire_device(&unresolved[ct], dev);
+			__aarp_expire_device(&proxies[ct], dev);
 		}
 
 		write_unlock_bh(&aarp_lock);

net/appletalk/ddp.c

@@ -647,9 +647,11 @@ static inline void atalk_dev_down(struct net_device *dev)
 static int ddp_device_event(struct notifier_block *this, unsigned long event,
 			    void *ptr)
 {
+	struct net_device *dev = ptr;
+
 	if (event == NETDEV_DOWN)
 		/* Discard any use of this */
-		atalk_dev_down(ptr);
+		atalk_dev_down(dev);
 
 	return NOTIFY_DONE;
 }