net: macb: Migrate to dev_pm_ops

Migrate the suspend/resume functions to use the dev_pm_ops PM interface.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>