ixgbevf: Fix IPv6 GSO type checks

Based on patch from Sridhar Samudrala

The following patch fixes the check for IPv6 GSO packet in ixgbevf
driver to use skb_is_gso_v6(). SKB_GSO_DODGY is also set
when packets are forwarded from a guest.

CC: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ixgbevf/ixgbevf_main.c b/drivers/net/ixgbevf/ixgbevf_main.c
index 623353db1..7b3af10 100644
--- a/drivers/net/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ixgbevf/ixgbevf_main.c
@@ -2781,7 +2781,7 @@
 								 IPPROTO_TCP,
 								 0);
 			adapter->hw_tso_ctxt++;
-		} else if (skb_shinfo(skb)->gso_type == SKB_GSO_TCPV6) {
+		} else if (skb_is_gso_v6(skb)) {
 			ipv6_hdr(skb)->payload_len = 0;
 			tcp_hdr(skb)->check =
 			    ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,