mac80211: return if CSA is not handle

If channel contexts are enabled, the CSA should not be processed
further. A return is missing here.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 481d503..0955630 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -789,6 +789,7 @@
 			   "not handling channel switch with channel contexts\n");
 		ieee80211_queue_work(&sdata->local->hw,
 				     &ifmgd->csa_connection_drop_work);
+		return;
 	}
 
 	mutex_lock(&sdata->local->chanctx_mtx);