cfg80211: fix warning when using WEXT for IBSS

Fix kernel warning when using WEXT for configuring ad-hoc mode,
e.g.  "iwconfig wlan0 essid test channel 1"

WARNING: at net/wireless/chan.c:373 cfg80211_chandef_usable+0x50/0x21c [cfg80211]()

The warning is caused by an uninitialized variable center_freq1.

Cc: stable@vger.kernel.org
Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/ibss.c

@@ -263,6 +263,8 @@ int cfg80211_ibss_wext_join(struct cfg80211_registered_device *rdev,
 				if (chan->flags & IEEE80211_CHAN_DISABLED)
 					continue;
 				wdev->wext.ibss.chandef.chan = chan;
+				wdev->wext.ibss.chandef.center_freq1 =
+					chan->center_freq;
 				break;
 			}
 
@@ -347,6 +349,7 @@ int cfg80211_ibss_wext_siwfreq(struct net_device *dev,
 	if (chan) {
 		wdev->wext.ibss.chandef.chan = chan;
 		wdev->wext.ibss.chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
+		wdev->wext.ibss.chandef.center_freq1 = freq;
 		wdev->wext.ibss.channel_fixed = true;
 	} else {
 		/* cfg80211_ibss_wext_join will pick one if needed */