atl1: add netconsole support

Copied from b44 driver, but it works:

netconsole: device eth0 not up yet, forcing it
atl1: eth0 link is up 100 Mbps full duplex
netconsole: network logging started

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>