watchdog: mediatek: mt8186: add wdt support

Support MT8186 watchdog device.

Signed-off-by: Runyang Chen <runyang.chen@mediatek.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220301054405.25021-4-rex-bc.chen@mediatek.com


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