veth: Update features to include all tunnel GSO types

This patch adds support for the checksum enabled versions of UDP and GRE
tunnels.  With this change we should be able to send and receive GSO frames
of these types over the veth pair without needing to segment the packets.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>