ARM: dts: r8a7778: Add clock for CA9 CPU core

Improve hardware description by adding a clock property to the device
node corresponding to the CA9 CPU core.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7778.dtsi

@@ -33,6 +33,7 @@ cpu@0 {
 			compatible = "arm,cortex-a9";
 			reg = <0>;
 			clock-frequency = <800000000>;
+			clocks = <&z_clk>;
 		};
 	};