staging: unisys: Add s-Par visornic ethernet driver

This driver creates a network device when s-Par sends a device
create message to create network adapter on the visorbus. When
the message is received by visorbus, the visornic_probe function
is called and the netdev device is created and managed by the
visornic driver.

Signed-off-by: David Kershner <david.kershner@unisys.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>