* Freescale i.MX Watchdog Timer (WDT) Controller

Required properties:
- compatible : Should be "fsl,<soc>-wdt"
- reg : Should contain WDT registers location and length
- interrupts : Should contain WDT interrupt

For imx8-wdt, it's a software watchdog which implemented by timer tick
in SCFW. In this case, only compatible name required.

Optional properties:
- big-endian: If present the watchdog device's registers are implemented
  in big endian mode, otherwise in native mode(same with CPU), for more
  detail please see: Documentation/devicetree/bindings/regmap/regmap.txt.
- fsl,ext-reset-output: If present the watchdog device is configured to
  assert its external reset (WDOG_B) instead of issuing a software reset.

Examples:

wdt@73f98000 {
	compatible = "fsl,imx51-wdt", "fsl,imx21-wdt";
	reg = <0x73f98000 0x4000>;
	interrupts = <58>;
	big-endian;
};