ARM AMBA Primecell SP805 Watchdog

Required properties:
- compatible: Should be "arm,sp805" & "arm,primecell"
- reg: Should contain location and length for watchdog timer register.
- interrupts: Should contain the list of watchdog timer interrupts.
- clocks: clocks driving the watchdog timer hardware. This list should be 2
	clocks. With 2 clocks, the order is wdogclk clock, apb_pclk.

Example:
	watchdog@66090000 {
		compatible = "arm,sp805", "arm,primecell";
		reg = <0x66090000 0x1000>;
		interrupts = <GIC_SPI 406 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&apb_pclk>,<&apb_pclk>;
		clock-names = "wdogclk", "apb_pclk";
	};