TI-NSPIRE timer

Required properties:

- compatible : should be "lsi,zevio-timer".
- reg : The physical base address and size of the timer (always first).
- clocks: phandle to the source clock.

Optional properties:

- interrupts : The interrupt number of the first timer.
- reg : The interrupt acknowledgement registers
	(always after timer base address)

If any of the optional properties are not given, the timer is added as a
clock-source only.

Example:

timer {
	compatible = "lsi,zevio-timer";
	reg = <0x900D0000 0x1000>, <0x900A0020 0x8>;
	interrupts = <19>;
	clocks = <&timer_clk>;
};

Example (no clock-events):

timer {
	compatible = "lsi,zevio-timer";
	reg = <0x900D0000 0x1000>;
	clocks = <&timer_clk>;
};