myri10ge: report when the link partner is running in Myrinet mode

Since Myri-10G boards may also run in Myrinet mode instead of Ethernet,
add a message when we detect that the link partner is not running in the
right mode.

Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>