net: Add fraglist GRO/GSO feature flags

This adds new Fraglist GRO/GSO feature flags. They will be used
to configure fraglist GRO/GSO what will be implemented with some
followup paches.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>