net/mlx5e: Trust kernel regarding transport offset

After AF_PACKET is fixed to calculate the transport header offset
correctly, trust the value set by the kernel. If the offset wasn't set,
it means there is no transport header in the packet.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/en_tx.c

@@ -148,12 +148,8 @@ static inline int mlx5e_skb_l2_header_offset(struct sk_buff *skb)
 
 static inline int mlx5e_skb_l3_header_offset(struct sk_buff *skb)
 {
-	struct flow_keys keys;
-
 	if (skb_transport_header_was_set(skb))
 		return skb_transport_offset(skb);
-	else if (skb_flow_dissect_flow_keys(skb, &keys, 0))
-		return keys.control.thoff;
 	else
 		return mlx5e_skb_l2_header_offset(skb);
 }