wifi: nl80211: require MLD address on link STA add/modify

We always need the MLD address and link ID to add or
modify the link STA, so require it in the API.

Fixes: 577e5b8c39 ("wifi: cfg80211: add API to add/modify/remove a link station")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -15827,14 +15827,13 @@ nl80211_add_mod_link_station(struct sk_buff *skb, struct genl_info *info,
 	if (add && !info->attrs[NL80211_ATTR_MAC])
 		return -EINVAL;
 
-	if (add && !info->attrs[NL80211_ATTR_MLD_ADDR])
+	if (!info->attrs[NL80211_ATTR_MLD_ADDR])
 		return -EINVAL;
 
 	if (add && !info->attrs[NL80211_ATTR_STA_SUPPORTED_RATES])
 		return -EINVAL;
 
-	if (info->attrs[NL80211_ATTR_MLD_ADDR])
-		params.mld_mac = nla_data(info->attrs[NL80211_ATTR_MLD_ADDR]);
+	params.mld_mac = nla_data(info->attrs[NL80211_ATTR_MLD_ADDR]);
 
 	if (info->attrs[NL80211_ATTR_MAC]) {
 		params.link_mac = nla_data(info->attrs[NL80211_ATTR_MAC]);