Mediatek SoCs Watchdog timer

Required properties:

- compatible should contain:
	"mediatek,mt2701-wdt", "mediatek,mt6589-wdt": for MT2701
	"mediatek,mt6589-wdt": for MT6589
	"mediatek,mt6797-wdt", "mediatek,mt6589-wdt": for MT6797
	"mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622
	"mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623
	"mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for MT7629

- reg : Specifies base physical address and size of the registers.

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

Example:

wdt: watchdog@10000000 {
	compatible = "mediatek,mt6589-wdt";
	reg = <0x10000000 0x18>;
	timeout-sec = <10>;
};