dt-bindings: watchdog: Add compatible for Mediatek MT8195

This commit adds dt-binding documentation of watchdog for Mediatek MT8195 SoC
Platform.

Signed-off-by: Seiya Wang <seiya.wang@mediatek.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210319023427.16711-5-seiya.wang@mediatek.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>