ARM: sun8i: a83t: cubietruck-plus: Enable PMIC part of AXP818 PMIC

The AXP813/AXP818 PMICs used with the A83T/H8 SoCs are actually 2 dies
in one package sharing the serial bus (I2C/RSB) pins. One die is the
actual PMIC. The other is an AC100 codec / RTC combo chip.

This patch enables the RSB controller and adds a device node for the
PMIC die to the Cubietruck Plus device tree. Since the AXP813 and
AXP818 are virtually identical, this patch uses the compatible string
for the former as a fallback.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts

@@ -129,6 +129,17 @@ &mmc2 {
 	status = "okay";
 };
 
+&r_rsb {
+	status = "okay";
+
+	axp81x: pmic@3a3 {
+		compatible = "x-powers,axp818", "x-powers,axp813";
+		reg = <0x3a3>;
+		interrupt-parent = <&r_intc>;
+		interrupts = <0 IRQ_TYPE_LEVEL_LOW>;
+	};
+};
+
 &spdif {
 	status = "okay";
 };