* sun4i/sun7i Real Time Clock

RTC controller for the Allwinner A10/A20

Required properties:
- compatible : Should be "allwinner,sun4i-rtc" or "allwinner,sun7i-a20-rtc"
- reg: physical base address of the controller and length of memory mapped
  region.
- interrupts: IRQ line for the RTC.

Example:

rtc: rtc@01c20d00 {
	compatible = "allwinner,sun4i-rtc";
	reg = <0x01c20d00 0x20>;
	interrupts = <24>;
};