libertas: Fine grained configuration of wake-on-lan.

Based on a patch from Shailendra Govardhan <shailen@marvell.com>.
This patch allows implementation of more specific wake-on-lan rules than those
of ethtool.

Please note that only firmware 5.110.22.p20 and above supports this feature.

This patch only implements the driver/firmware interface, not the
userspace/driver interface.

Signed-off-by: Anna Neal <anna@cozybit.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>