cfg80211: fix missing break in NL8211_CHAN_WIDTH_80P80 case

The switch on chandef->width is missing a break on the
NL8211_CHAN_WIDTH_80P80 case; currently we get a WARN_ON when
center_freq2 is non-zero because of the missing break.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/chan.c

@@ -513,6 +513,7 @@ static bool cfg80211_chandef_dfs_available(struct wiphy *wiphy,
 		r = cfg80211_get_chans_dfs_available(wiphy,
 						     chandef->center_freq2,
 						     width);
+		break;
 	default:
 		WARN_ON(chandef->center_freq2);
 		break;