mac80211: Do not scan for IBSS merge with a fixed BSSID.

Currently, when we are on an IBSS network with no active station,
we would scan for other BSSID, even if fixed_bssid is on,  due to
a bug in ibss.c,  where fixed_channel would be checked instead of
fixed_bssid.  This would trigger useless scans where scan results
would not be used anyway.

This patch also reverts commit 39d02a7d90602d4557ee05db2a157a4e0,
which assumed that the ifibss->fixed_channel check was legitimate
to disable single-channel scans.  IBSS single-channel scan should
now be fixed.

Signed-off-by: Nicolas Cavallari <cavallar@lri.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/ibss.c

@@ -655,14 +655,15 @@ static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
 	if (ieee80211_sta_active_ibss(sdata))
 		return;
 
-	if (ifibss->fixed_channel)
+	if (ifibss->fixed_bssid)
 		return;
 
 	printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
 	       "IBSS networks with same SSID (merge)\n", sdata->name);
 
 	ieee80211_request_internal_scan(sdata,
-			ifibss->ssid, ifibss->ssid_len, NULL);
+			ifibss->ssid, ifibss->ssid_len,
+			ifibss->fixed_channel ? ifibss->channel : NULL);
 }
 
 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)