dt-bindings: watchdog: mediatek: add support for MediaTek MT7623 and MT7622 SoC

This updates dt-binding documentation for MediaTek MT7622 and
MT7623 SoC. For the both SoCs supported all rely on the fallback
binding of the case with "mediatek,mt6589-wdt".
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Documentation/devicetree/bindings/watchdog/mtk-wdt.txt

@@ -4,6 +4,8 @@ Required properties:
 
 - compatible should contain:
 	* "mediatek,mt2701-wdt" for MT2701 compatible watchdog timers
+	* "mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622
+	* "mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623
 	* "mediatek,mt6589-wdt" for all compatible watchdog timers (MT2701,
 		MT6589)