ARM: kirkwood: Introduce MBus DT node

Add a minimal MBus node, just to allow the MBus driver to probe.
Follow-up patches will migrate the rest of the nodes appropriately.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

arch/arm/boot/dts/kirkwood.dtsi

@@ -28,6 +28,11 @@
 		      <0xf1020214 0x04>;
 	};
 
+	mbus {
+		compatible = "marvell,kirkwood-mbus", "simple-bus";
+		controller = <&mbusc>;
+	};
+
 	ocp@f1000000 {
 		compatible = "simple-bus";
 		ranges = <0x00000000 0xf1000000 0x0100000
@@ -37,6 +42,11 @@
 		#address-cells = <1>;
 		#size-cells = <1>;
 
+		mbusc: mbus-controller@20000 {
+			compatible = "marvell,mbus-controller";
+			reg = <0x20000 0x80>, <0x1500 0x20>;
+		};
+
 		core_clk: core-clocks@10030 {
 			compatible = "marvell,kirkwood-core-clock";
 			reg = <0x10030 0x4>;