Blackfin EMAC Driver: Functional power management support

Reprogram MAC address after resume from Suspend Mem
(Blackfin Hibernate looses all CORE and SYSTEM register content)

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>