CRIS: add Axis 88 board device tree

Add a minimal device tree for the ETRAX FS SoC and the Axis 88 developer
board.

Signed-off-by: Rabin Vincent <[e-mail]>
Signed-off-by: Jesper Nilsson <[e-mail]>

arch/cris/boot/dts/dev88.dts

···
+/dts-v1/;
+
+/include/ "etraxfs.dtsi"
+
+/ {
+	model = "Axis 88 Developer Board";
+	compatible = "axis,dev88";
+
+	aliases {
+		serial0 = &uart0;
+	};
+
+	soc {
+		uart0: serial@b00260000 {
+			status = "okay";
+		};
+	};
+};

arch/cris/boot/dts/etraxfs.dtsi

···
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+	interrupt-parent = <&intc>;
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			device_type = "cpu";
+			model = "axis,crisv32";
+			reg = <0>;
+		};
+	};
+
+	soc {
+		compatible = "simple-bus";
+		model = "etraxfs";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		intc: interrupt-controller {
+			compatible = "axis,crisv32-intc";
+			reg = <0xb001c000 0x1000>;
+			interrupt-controller;
+			#interrupt-cells = <1>;
+		};
+
+		serial@b00260000 {
+			compatible = "axis,etraxfs-uart";
+			reg = <0xb0026000 0x1000>;
+			interrupts = <68>;
+			status = "disabled";
+		};
+	};
+};