skge: Enable WoL by default if supported

If skge hardware is capable of waking up the system from sleep,
enable magic packet WoL during driver initialisation.

This makes WoL work without calling 'ethtool -s ethX wol g'
for each adapter.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Michael Guntsche <mike@it-loops.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>