ARM: dts: orion5x: Add required properties for orion-wdt to DT node

orion-wdt refuses to start without these properties defined, so lift
definitions out of kirkwood/dove.dtsi

[gregory.clement@free-electrons.com: fix commit title]
Signed-off-by: Jamie Lentin <jm@lentin.co.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>