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>