mac80211: send auth in IBSS only if userspace isn't handling it

Check the auth frame registration count before sending
"open system" authentication messages when a new station
registers on a particular IBSS network. This stops us
from sending out multiple authentication messages with
different authentication algorithms.
Signed-off-by: Will Hawkins <hawkinsw@opentechinstitute.org>
[reword commit message a bit]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ibss.c

@@ -279,7 +279,7 @@ static struct sta_info *ieee80211_ibss_finish_sta(struct sta_info *sta,
 	/* If it fails, maybe we raced another insertion? */
 	if (sta_info_insert_rcu(sta))
 		return sta_info_get(sdata, addr);
-	if (auth) {
+	if (auth && !sdata->u.ibss.auth_frame_registrations) {
 		ibss_vdbg("TX Auth SA=%pM DA=%pM BSSID=%pM (auth_transaction=1)\n",
 			  sdata->vif.addr, sdata->u.ibss.bssid, addr);
 		ieee80211_send_auth(sdata, 1, WLAN_AUTH_OPEN, NULL, 0,