sfc: Stop changing header offsets on TX

There is nothing in the VLAN driver or core VLAN support that
invalidates the TCP and IP header offsets.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

drivers/net/ethernet/sfc/tx.c

@@ -651,17 +651,8 @@ static __be16 efx_tso_check_protocol(struct sk_buff *skb)
 	EFX_BUG_ON_PARANOID(((struct ethhdr *)skb->data)->h_proto !=
 			    protocol);
 	if (protocol == htons(ETH_P_8021Q)) {
-		/* Find the encapsulated protocol; reset network header
-		 * and transport header based on that. */
 		struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
 		protocol = veh->h_vlan_encapsulated_proto;
-		skb_set_network_header(skb, sizeof(*veh));
-		if (protocol == htons(ETH_P_IP))
-			skb_set_transport_header(skb, sizeof(*veh) +
-						 4 * ip_hdr(skb)->ihl);
-		else if (protocol == htons(ETH_P_IPV6))
-			skb_set_transport_header(skb, sizeof(*veh) +
-						 sizeof(struct ipv6hdr));
 	}
 
 	if (protocol == htons(ETH_P_IP)) {