Broadcom 3390 Watchdog timer

Required properties:

- compatible : should be "brcm,bcm3390-wdt"
- reg : Specifies base physical address and size of the registers.

Optional properties:

- clocks: The clock running the watchdog. If no clock is found the
	  driver will default to 27000000 Hz.
- interrupts: For pretimeout and halftimeout condition. This will only be
	available if CONFIG_BCM3390_WDT_NMI is not defined.
- timeout-ms: The watchdog timeout value to use as a default. If not specified
	a built-in default value will be used.
- mode: One of the following:
	"reset": Reset when the timer expires (default if not specified)
	"nmi": Trigger an NMI (FIQ) to the CPU when the timer expires
	"nmi-reset": Trigger an NMI when the timer reaches 1/2-way and a
	reset when it expires.

	The ability to use the NMI functionality is only available if
	CONFIG_BCM3390_WDT_NMI is defined.
- start: Start the watchdog if any of the watchdog devices passed to this
	driver's probe function are running. Running watchdog devices passed
	to this driver's probe function will be stopped regardless of this
	property's presence or absence.


Example:

	watchdog@f040a100 {
		clock-frequency = <0x19bfcc0>;
		compatible = "brcm,bcm3390-wdt";
		reg = <0xf040a100 0x40>;
		interrupts = <0 40 0>;
		interrupt-parent = <&gic>;
		interrupt-names = "wd_timeout";
		timeout-ms = <60000>;
		mode = "nmi-reset";
		start;
	};

	watchdog@f10b0900 {
		clock-frequency = <0x19bfcc0>;
		compatible = "brcm,bcm3390-wdt";
		reg = <0xf10b0900 0x40>;
		interrupts = <0 40 0>;
		interrupt-parent = <&gic>;
		interrupt-names = "wd_timeout";
	};
