i40e/i40evf: Add support for IPIP and SIT offloads

Looking over the documentation it turns out enabling IPIP and SIT offloads
for i40e is pretty straightforward.  As such I decided to enable them with
this patch.  In my testing I am seeing an improvement of 8 to 10 Gb/s
for IPIP and SIT tunnels with this offload enabled.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index f2e83fe..ec94ad6c 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -9120,6 +9120,8 @@
 				   NETIF_F_TSO_ECN		|
 				   NETIF_F_TSO6			|
 				   NETIF_F_GSO_GRE		|
+				   NETIF_F_GSO_IPIP		|
+				   NETIF_F_GSO_SIT		|
 				   NETIF_F_GSO_UDP_TUNNEL	|
 				   NETIF_F_GSO_UDP_TUNNEL_CSUM	|
 				   NETIF_F_SCTP_CRC		|