netdev: bfin_mac: add support for wake-on-lan magic packets

Note that WOL works only in PM Suspend Standby Mode (Sleep Mode).

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: David S. Miller <davem@davemloft.net>