[ARM] orion5x: D-link DNS-323 rev. B1 power-off

This patch fixes power LED blinking and power-off on DNS-323 rev. B1.

GPIO pin 3 has to be set to 1 to stop power LED blinking and to allow the LED to be controlled via leds-gpio. This pin has to be also set to 1 for power-off to work.
To power-off the rev. B1 machine, pin 8 has to be set to 1 and then set to 0 to do actual power-off.

Tested on my DNS-323 rev. B1

Signed-off-by: Erik Benada <erikbenada@yahoo.ca>
Signed-off-by: Nicolas Pitre <nico@marvell.com>