wifi: mt76: fix switch default case in mt7996_reverse_frag0_hdr_trans

The switch default case for frame_contorl is invalid. Return -EINVAL
error for it.

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/mac.c

@@ -469,7 +469,7 @@ static int mt7996_reverse_frag0_hdr_trans(struct sk_buff *skb, u16 hdr_gap)
 		ether_addr_copy(hdr.addr4, eth_hdr->h_source);
 		break;
 	default:
-		break;
+		return -EINVAL;
 	}
 
 	skb_pull(skb, hdr_gap + sizeof(struct ethhdr) - 2);