watchdog: mt8192: add wdt support

Add support for watchdog device found in MT8192 SoC

Signed-off-by: Crystal Guo <crystal.guo@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20201014131936.20584-5-crystal.guo@mediatek.com


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