Faraday Technology timer

This timer is a generic IP block from Faraday Technology, embedded in the
Cortina Systems Gemini SoCs and other designs.

Required properties:

- compatible : Must be one of
  "faraday,fttmr010"
  "cortina,gemini-timer", "faraday,fttmr010"
  "moxa,moxart-timer", "faraday,fttmr010"
  "aspeed,ast2400-timer"
  "aspeed,ast2500-timer"
  "aspeed,ast2600-timer"

- reg : Should contain registers location and length
- interrupts : Should contain the three timer interrupts usually with
  flags for falling edge

Optionally required properties:

- clocks : a clock to provide the tick rate for "faraday,fttmr010"
- clock-names : should be "EXTCLK" and "PCLK" for the external tick timer
  and peripheral clock respectively, for "faraday,fttmr010"
- syscon : a phandle to the global Gemini system controller if the compatible
  type is "cortina,gemini-timer"

Example:

timer@43000000 {
	compatible = "faraday,fttmr010";
	reg = <0x43000000 0x1000>;
	interrupts = <14 IRQ_TYPE_EDGE_FALLING>, /* Timer 1 */
		   <15 IRQ_TYPE_EDGE_FALLING>, /* Timer 2 */
		   <16 IRQ_TYPE_EDGE_FALLING>; /* Timer 3 */
	clocks = <&extclk>, <&pclk>;
	clock-names = "EXTCLK", "PCLK";
};