DM9000: Wake on LAN support

Add support for Wake on LAN (WOL) reception and waking the device up from
this signal via the ethtool interface. Currently we are only supporting
the magic-packet variant of wakeup.

WOL is enabled by specifying a second interrupt resource to the driver
which indicates where the interrupt for the WOL is being signalled. This
then enables the necessary ethtool calls to leave the device in a state
to receive WOL frames when going into suspend.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>