* sun6i Real Time Clock

RTC controller for the Allwinner A31

Required properties:
- compatible	: Should be "allwinner,sun6i-a31-rtc"
- reg		: physical base address of the controller and length of
		  memory mapped region.
- interrupts	: IRQ lines for the RTC alarm 0 and alarm 1, in that order.

Required properties for new device trees
- clocks	: phandle to the 32kHz external oscillator
- clock-output-names : name of the LOSC clock created
- #clock-cells  : must be equals to 1. The RTC provides two clocks: the
		  LOSC and its external output, with index 0 and 1
		  respectively.

Example:

rtc: rtc@01f00000 {
	compatible = "allwinner,sun6i-a31-rtc";
	reg = <0x01f00000 0x54>;
	interrupts = <0 40 4>, <0 41 4>;
	clock-output-names = "osc32k";
	clocks = <&ext_osc32k>;
	#clock-cells = <1>;
};