cfg80211: allow registering to beacons

Add the ability to register to received beacon frames
to allow implementing OLBC logic in userspace. The
registration is per wiphy since there's no point in
receiving the same frame multiple times.

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

net/wireless/core.h

@@ -54,6 +54,8 @@ struct cfg80211_registered_device {
 	int opencount; /* also protected by devlist_mtx */
 	wait_queue_head_t dev_wait;
 
+	u32 ap_beacons_nlpid;
+
 	/* BSSes/scanning */
 	spinlock_t bss_lock;
 	struct list_head bss_list;