nl80211: fix potential leak in AP start

If nl80211_parse_he_obss_pd() fails, we leak the previously
allocated ACL memory. Free it in this case.

Fixes: 796e90f42b ("cfg80211: add support for parsing OBBS_PD attributes")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20200221104142.835aba4cdd14.I1923b55ba9989c57e13978f91f40bfdc45e60cbd@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -4800,8 +4800,7 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 		err = nl80211_parse_he_obss_pd(
 					info->attrs[NL80211_ATTR_HE_OBSS_PD],
 					&params.he_obss_pd);
-		if (err)
-			return err;
+		goto out;
 	}
 
 	nl80211_calculate_ap_params(&params);
@@ -4823,6 +4822,7 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 	}
 	wdev_unlock(wdev);
 
+out:
 	kfree(params.acl);
 
 	return err;