mac80211: Fix error introduced in netdev_mc_count() changes.

Commit 4cd24eaf
("net: use netdev_mc_count and netdev_mc_empty when appropriate")
added this hunk to net/mac80211/iface.c:

 	__dev_addr_unsync(&local->mc_list, &local->mc_count,
-			  &dev->mc_list, &dev->mc_count);
+			  &dev->mc_list, dev->mc_count);

which is definitely not correct, introduced a warning (reported
by Stephen Rothwell):

net/mac80211/iface.c: In function 'ieee80211_stop':
net/mac80211/iface.c:416: warning: passing argument 4 of '__dev_addr_unsync' makes pointer from integer without a cast
include/linux/netdevice.h:1967: note: expected 'int *' but argument is of type 'int'

and is thus reverted here.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/mac80211/iface.c

@@ -413,7 +413,7 @@ static int ieee80211_stop(struct net_device *dev)
 	netif_addr_lock_bh(dev);
 	spin_lock_bh(&local->filter_lock);
 	__dev_addr_unsync(&local->mc_list, &local->mc_count,
-			  &dev->mc_list, dev->mc_count);
+			  &dev->mc_list, &dev->mc_count);
 	spin_unlock_bh(&local->filter_lock);
 	netif_addr_unlock_bh(dev);