nl80211: allow configuring IBSS beacon interval

Make the JOIN_IBSS command look at the beacon interval
attribute to see if the user requested a specific beacon
interval, if not default to 100 TU (wext too).

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
index b5c601e..3c38afa 100644
--- a/net/wireless/ibss.c
+++ b/net/wireless/ibss.c
@@ -116,6 +116,9 @@
 	enum ieee80211_band band;
 	int i;
 
+	if (!wdev->wext.beacon_interval)
+		wdev->wext.beacon_interval = 100;
+
 	/* try to find an IBSS channel if none requested ... */
 	if (!wdev->wext.channel) {
 		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {