wifi: mt76: mt7996: fix bss wlan_idx when sending bss_info command

The bmc_tx_wlan_idx should be the wlan_idx of the current bss rather
than peer AP's wlan_idx, otherwise there will appear some frame
decryption problems on station mode.

Fixes: 98686cd2 ("wifi: mt76: mt7996: add driver for MediaTek Wi-Fi 7 (802.11be) devices")
Reviewed-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7996/mcu.c

@@ -712,6 +712,7 @@ mt7996_mcu_bss_basic_tlv(struct sk_buff *skb,
 	struct cfg80211_chan_def *chandef = &phy->chandef;
 	struct mt76_connac_bss_basic_tlv *bss;
 	u32 type = CONNECTION_INFRA_AP;
+	u16 sta_wlan_idx = wlan_idx;
 	struct tlv *tlv;
 	int idx;
 
@@ -731,7 +732,7 @@ mt7996_mcu_bss_basic_tlv(struct sk_buff *skb,
 				struct mt76_wcid *wcid;
 
 				wcid = (struct mt76_wcid *)sta->drv_priv;
-				wlan_idx = wcid->idx;
+				sta_wlan_idx = wcid->idx;
 			}
 			rcu_read_unlock();
 		}
@@ -751,7 +752,7 @@ mt7996_mcu_bss_basic_tlv(struct sk_buff *skb,
 	bss->bcn_interval = cpu_to_le16(vif->bss_conf.beacon_int);
 	bss->dtim_period = vif->bss_conf.dtim_period;
 	bss->bmc_tx_wlan_idx = cpu_to_le16(wlan_idx);
-	bss->sta_idx = cpu_to_le16(wlan_idx);
+	bss->sta_idx = cpu_to_le16(sta_wlan_idx);
 	bss->conn_type = cpu_to_le32(type);
 	bss->omac_idx = mvif->omac_idx;
 	bss->band_idx = mvif->band_idx;