ARM: shmobile: ape6evm: add CPUFreq support

This patch adds OPPs to the CA15 DT node and a max8973 DT node to support
clock and voltage scaling, using the cpufreq-cpu0 CPUFreq driver.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a73a4-ape6evm.dts

@@ -50,3 +50,25 @@
 		};
 	};
 };
+
+&i2c5 {
+	vdd_dvfs: max8973@1b {
+		compatible = "maxim,max8973";
+		reg = <0x1b>;
+
+		regulator-min-microvolt = <935000>;
+		regulator-max-microvolt = <1200000>;
+		regulator-boot-on;
+		regulator-always-on;
+	};
+};
+
+&cpu0 {
+	cpu0-supply = <&vdd_dvfs>;
+	operating-points = <
+		/* kHz  uV */
+		1950000 1115000
+		1462500  995000
+	>;
+	voltage-tolerance = <1>; /* 1% */
+};