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: NJamie Lentin <jm@lentin.co.uk>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>

arch/arm/boot/dts/orion5x.dtsi

@@ -144,9 +144,10 @@
 
 			wdt: wdt@20300 {
 				compatible = "marvell,orion-wdt";
-				reg = <0x20300 0x28>;
+				reg = <0x20300 0x28>, <0x20108 0x4>;
 				interrupt-parent = <&bridge_intc>;
 				interrupts = <3>;
+				clocks = <&core_clk 0>;
 				status = "okay";
 			};