mac80211: optimise station flags

The flaglock in struct sta_info has long been
something that I wanted to get rid of, this
finally does the conversion to atomic bitops.

The conversion itself is straight-forward in
most places, a few things needed to change a
bit since we can no longer use multiple bits
at the same time.

On x86-64, this is a fairly significant code
size reduction:
   text	   data	    bss	    dec	    hex
 427861	  23648	   1008	 452517	  6e7a5	before
 425383	  23648	    976	 450007	  6ddd7	after

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/iface.c

@@ -299,8 +299,8 @@ static int ieee80211_do_open(struct net_device *dev, bool coming_up)
 			goto err_del_interface;
 		}
 
-		/* no locking required since STA is not live yet */
-		sta->flags |= WLAN_STA_AUTHORIZED;
+		/* no atomic bitop required since STA is not live yet */
+		set_sta_flag(sta, WLAN_STA_AUTHORIZED);
 
 		res = sta_info_insert(sta);
 		if (res) {