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

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

Optional properties:
- has-tpo: Decides if the wakeup is supported or not.

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