mips: dts: realtek: add device_type property to cpu node

Add device_type = "cpu" to the cpu node for the rtl838x SoC. This
resolves the following dtbs_check complaint:

 cpus: cpu@0: 'cache-level' is a required property

Signed-off-by: Chris Packham <[email protected]>
Reviewed-by: Marek Behún <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>

Author: cpackham-atlnz

arch/mips/boot/dts/realtek/rtl838x.dtsi

@@ -6,6 +6,7 @@
 		#size-cells = <0>;
 
 		cpu@0 {
+			device_type = "cpu";
 			compatible = "mips,mips4KEc";
 			reg = <0>;
 			clocks = <&baseclk 0>;