ARM: dts: r8a7794: Add L2 cache-controller node

Add a device node for the L2 cache, and link the CPU nodes to it.

The L2 cache for the Cortex-A7 CPU cores is 512 KiB large (organized as
64 KiB x 8 ways).

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Simon Horman <[e-mail]>

arch/arm/boot/dts/r8a7794.dtsi

···
 			compatible = "arm,cortex-a7";
 			reg = <0>;
 			clock-frequency = <1000000000>;
+			next-level-cache = <&L2_CA7>;
 		};
 
 		cpu1: cpu@1 {
···
 			compatible = "arm,cortex-a7";
 			reg = <1>;
 			clock-frequency = <1000000000>;
+			next-level-cache = <&L2_CA7>;
 		};
+	};
+
+	L2_CA7: cache-controller@1 {
+		compatible = "cache";
+		cache-unified;
+		cache-level = <2>;
 	};
 
 	gic: interrupt-controller@f1001000 {