Technologic Systems Watchdog

Required properties:
- compatible: must be "technologic,ts4800-wdt"
- syscon: phandle / integer array that points to the syscon node which
          describes the FPGA's syscon registers.
          - phandle to FPGA's syscon
          - offset to the watchdog register

Optional property:
- timeout-sec: contains the watchdog timeout in seconds.

Example:

syscon: syscon@b0010000 {
	compatible = "syscon", "simple-mfd";
	reg = <0xb0010000 0x3d>;
	reg-io-width = <2>;

	wdt@e {
		compatible = "technologic,ts4800-wdt";
		syscon = <&syscon 0xe>;
		timeout-sec = <10>;
	};
}