mac80211: IBSS: avoid unneeded return value processing

when ieee80211_ibss_csa_beacon() fails, we return it's value.
When it succeeds, we basically copy it's value and also .. return it.

Just return it immediately, simplifying the code.
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Link: https://lore.kernel.org/r/20190911141431.12498-1-koen.vandeputte@ncentric.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ibss.c

@@ -538,7 +538,6 @@ int ieee80211_ibss_finish_csa(struct ieee80211_sub_if_data *sdata)
 {
 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 	struct cfg80211_bss *cbss;
-	int err, changed = 0;
 
 	sdata_assert_lock(sdata);
 
@@ -560,13 +559,7 @@ int ieee80211_ibss_finish_csa(struct ieee80211_sub_if_data *sdata)
 	ifibss->chandef = sdata->csa_chandef;
 
 	/* generate the beacon */
-	err = ieee80211_ibss_csa_beacon(sdata, NULL);
-	if (err < 0)
-		return err;
-
-	changed |= err;
-
-	return changed;
+	return ieee80211_ibss_csa_beacon(sdata, NULL);
 }
 
 void ieee80211_ibss_stop(struct ieee80211_sub_if_data *sdata)