arm64: dts: mt8183: update watchdog device node

The watchdog driver for MT8183 relies on DT data, so the fallback
compatible MT6589 won't work, need to update watchdog device node
to sync with watchdog dt-binding document.

Signed-off-by: Crystal Guo <crystal.guo@mediatek.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>