ARM: shmobile: Add r8a7740 Maximum CPU Frequency to DTS

Add 800 MHz to the r8a7740 DTS to describe the maximum CPU frequency.
Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Tested-by: Geert Uytterhoeven <geert@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7740.dtsi

@@ -22,6 +22,7 @@ cpu@0 {
 			compatible = "arm,cortex-a9";
 			device_type = "cpu";
 			reg = <0x0>;
+			clock-frequency = <800000000>;
 		};
 	};