dt-bindings: wdog: mtk-wdt: add support for MT851

Add binding documentation of mtk-wdt for MT8516 SoC.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

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

@@ -9,6 +9,7 @@ Required properties:
 	"mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622
 	"mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623
 	"mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for MT7629
+	"mediatek,mt8516-wdt", "mediatek,mt6589-wdt": for MT8516
 
 - reg : Specifies base physical address and size of the registers.