nl80211: suppress smatch warnings

smatch warns that we once checked request->ssids in two functions
and then unconditionally used it later again.

This is actually fine, because the code has a relationship between
attrs[NL80211_ATTR_SCAN_SSIDS], n_ssids and request->ssids, but
smatch isn't smart enough to realize that.

Suppress the warnings by always checking just n_ssids - that way
smatch won't know that request->ssids could be NULL, and since it
is only NULL when n_ssids is 0 we still check everything correctly.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -5776,7 +5776,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 		request->ssids = (void *)&request->channels[n_channels];
 	request->n_ssids = n_ssids;
 	if (ie_len) {
-		if (request->ssids)
+		if (n_ssids)
 			request->ie = (void *)(request->ssids + n_ssids);
 		else
 			request->ie = (void *)(request->channels + n_channels);
@@ -5832,7 +5832,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 	request->n_channels = i;
 
 	i = 0;
-	if (info->attrs[NL80211_ATTR_SCAN_SSIDS]) {
+	if (n_ssids) {
 		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS], tmp) {
 			if (nla_len(attr) > IEEE80211_MAX_SSID_LEN) {
 				err = -EINVAL;
@@ -6030,7 +6030,7 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 		request->ssids = (void *)&request->channels[n_channels];
 	request->n_ssids = n_ssids;
 	if (ie_len) {
-		if (request->ssids)
+		if (n_ssids)
 			request->ie = (void *)(request->ssids + n_ssids);
 		else
 			request->ie = (void *)(request->channels + n_channels);
@@ -6039,7 +6039,7 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 	if (n_match_sets) {
 		if (request->ie)
 			request->match_sets = (void *)(request->ie + ie_len);
-		else if (request->ssids)
+		else if (n_ssids)
 			request->match_sets =
 				(void *)(request->ssids + n_ssids);
 		else
@@ -6098,7 +6098,7 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 	request->n_channels = i;
 
 	i = 0;
-	if (attrs[NL80211_ATTR_SCAN_SSIDS]) {
+	if (n_ssids) {
 		nla_for_each_nested(attr, attrs[NL80211_ATTR_SCAN_SSIDS],
 				    tmp) {
 			if (nla_len(attr) > IEEE80211_MAX_SSID_LEN) {