myri10ge: improve port type reporting in ethtool

Improve the reporting of myri10ge port type in ethtool,
and update for new boards.

Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: Andrew Gallatin <gallatin@myri.com>
Signed-off-by: David S. Miller <davem@davemloft.net>