hv_netvsc: use new helper tcp_v6_gso_csum_prep

Use new helper tcp_v6_gso_csum_prep in additional network drivers.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/hyperv/netvsc_drv.c

@@ -638,10 +638,7 @@ static int netvsc_xmit(struct sk_buff *skb, struct net_device *net, bool xdp_tx)
 		} else {
 			lso_info->lso_v2_transmit.ip_version =
 				NDIS_TCP_LARGE_SEND_OFFLOAD_IPV6;
-			ipv6_hdr(skb)->payload_len = 0;
-			tcp_hdr(skb)->check =
-				~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
-						 &ipv6_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
+			tcp_v6_gso_csum_prep(skb);
 		}
 		lso_info->lso_v2_transmit.tcp_header_offset = skb_transport_offset(skb);
 		lso_info->lso_v2_transmit.mss = skb_shinfo(skb)->gso_size;