MOXA ART timer

Required properties:

- compatible : Must be one of:
 	- "moxa,moxart-timer"
 	- "aspeed,ast2400-timer"
- reg : Should contain registers location and length
- interrupts : Should contain the timer interrupt number
- clocks : Should contain phandle for the clock that drives the counter

Example:

	timer: timer@98400000 {
		compatible = "moxa,moxart-timer";
		reg = <0x98400000 0x42>;
		interrupts = <19 1>;
		clocks = <&coreclk>;
	};