Make use of new common udp_tunnel_nic infra. ixgbe supports
IPv4 only, and only single VxLAN and Geneve ports (one each).
v2:
- split out the RXCSUM feature handling to separate change;
- declare structs separately;
- use ti.type instead of assuming table 0 is VxLAN;
- move setting netdev->udp_tunnel_nic_info to its own switch.
Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>