mt76: mt7915: fix potential memory leak of fw monitor packets

Free the skb of fw monitor packets.
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7915/mac.c

@@ -1733,6 +1733,7 @@ void mt7915_queue_rx_skb(struct mt76_dev *mdev, enum mt76_rxq_id q,
 		break;
 	case PKT_TYPE_RX_FW_MONITOR:
 		mt7915_debugfs_rx_fw_monitor(dev, skb->data, skb->len);
+		dev_kfree_skb(skb);
 		break;
 	case PKT_TYPE_NORMAL:
 		if (!mt7915_mac_fill_rx(dev, skb)) {