This patch implements platform_driver's .probe and .remove
routine, and also adds board specific private data structure.

This driver registers net_device at platform_driver's .probe
routine and unregisters net_device at its .remove routine.
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>