wifi: mt76: mt7996: fix memory leak in mt7996_mcu_exit

Always purge mcu skb queues in mt7996_mcu_exit routine even if
mt7996_firmware_state fails.

Fixes: 98686cd2 ("wifi: mt76: mt7996: add driver for MediaTek Wi-Fi 7 (802.11be) devices")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -2460,13 +2460,14 @@ void mt7996_mcu_exit(struct mt7996_dev *dev)
 	__mt76_mcu_restart(&dev->mt76);
 	if (mt7996_firmware_state(dev, false)) {
 		dev_err(dev->mt76.dev, "Failed to exit mcu\n");
-		return;
+		goto out;
 	}
 
 	mt76_wr(dev, MT_TOP_LPCR_HOST_BAND(0), MT_TOP_LPCR_HOST_FW_OWN);
 	if (dev->hif2)
 		mt76_wr(dev, MT_TOP_LPCR_HOST_BAND(1),
 			MT_TOP_LPCR_HOST_FW_OWN);
+out:
 	skb_queue_purge(&dev->mt76.mcu.res_q);
 }