wifi: mt76: mt7925: fix invalid array index in ssid assignment during hw scan

Update the destination index to use 'n_ssids', which is incremented only
when a valid SSID is present. Previously, both mt76_connac_mcu_hw_scan()
and mt7925_mcu_hw_scan() used the loop index 'i' for the destination
array, potentially leaving gaps if any source SSIDs had zero length.

Cc: stable@vger.kernel.org
Fixes: c948b5d ("wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 chips")
Signed-off-by: Michael Lo <michael.lo@mediatek.com>
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Link: https://patch.msgid.link/20250612062046.160598-1-mingyen.hsieh@mediatek.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>

Author: michaello316

drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c

@@ -1740,8 +1740,8 @@ int mt76_connac_mcu_hw_scan(struct mt76_phy *phy, struct ieee80211_vif *vif,
 		if (!sreq->ssids[i].ssid_len)
 			continue;
 
-		req->ssids[i].ssid_len = cpu_to_le32(sreq->ssids[i].ssid_len);
-		memcpy(req->ssids[i].ssid, sreq->ssids[i].ssid,
+		req->ssids[n_ssids].ssid_len = cpu_to_le32(sreq->ssids[i].ssid_len);
+		memcpy(req->ssids[n_ssids].ssid, sreq->ssids[i].ssid,
 		       sreq->ssids[i].ssid_len);
 		n_ssids++;
 	}

drivers/net/wireless/mediatek/mt76/mt7925/mcu.c

@@ -2869,8 +2869,8 @@ int mt7925_mcu_hw_scan(struct mt76_phy *phy, struct ieee80211_vif *vif,
 		if (i > MT7925_RNR_SCAN_MAX_BSSIDS)
 			break;
 
-		ssid->ssids[i].ssid_len = cpu_to_le32(sreq->ssids[i].ssid_len);
-		memcpy(ssid->ssids[i].ssid, sreq->ssids[i].ssid,
+		ssid->ssids[n_ssids].ssid_len = cpu_to_le32(sreq->ssids[i].ssid_len);
+		memcpy(ssid->ssids[n_ssids].ssid, sreq->ssids[i].ssid,
 		       sreq->ssids[i].ssid_len);
 		n_ssids++;
 	}