ionic: Add the basic NDO callbacks for netdev support

Set up the initial NDO structure and callbacks for netdev
to use, and register the netdev.  This will allow us to do
a few basic operations on the device, but no traffic yet.

Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>