Broadcom STB wake-up Timer

The Broadcom STB wake-up timer provides a 27Mhz resolution timer, with the
ability to wake up the system from low-power suspend/standby modes.

Required properties:
- compatible     : should contain "brcm,brcmstb-waketimer"
- reg            : the register start and length for the WKTMR block
- interrupts     : The TIMER interrupt
- interrupt-parent: The phandle to the Always-On (AON) Power Management (PM) L2
                    interrupt controller node
- clocks	 : The phandle to the UPG fixed clock (27Mhz domain)

Example:

waketimer@f0411580 {
	compatible = "brcm,brcmstb-waketimer";
	reg = <0xf0411580 0x14>;
	interrupts = <0x3>;
	interrupt-parent = <&aon_pm_l2_intc>;
	clocks = <&upg_fixed>;
};