IBM OPAL real-time clock
------------------------

Required properties:
- compatible: Should be "ibm,opal-rtc"

Optional properties:
- wakeup-source: Decides if the wakeup is supported or not
		 (Legacy property supported: "has-tpo")

Example:
	rtc {
		compatible = "ibm,opal-rtc";
		wakeup-source;
		phandle = <0x10000029>;
		linux,phandle = <0x10000029>;
	};
