mac80211: update oper_channel on ibss join

Commit 13c40c54 ("mac80211: Add HT operation modes for IBSS") broke
ibss operation by mistakenly removing the local->oper_channel
update (causing ibss to start on the wrong channel). fix it.
Signed-off-by: Eliad Peller <eliad@wizery.com>
Acked-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/ibss.c

@@ -106,6 +106,7 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 
 	sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
 
+	local->oper_channel = chan;
 	channel_type = ifibss->channel_type;
 	if (channel_type > NL80211_CHAN_HT20 &&
 	    !cfg80211_can_beacon_sec_chan(local->hw.wiphy, chan, channel_type))