watchdog: mediatek: Add support for MT6735 TOPRGU/WDT

Add support for the Top Reset Generation Unit/Watchdog Timer found on
MT6735.

Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20241106104738.195968-3-y.oudjana@protonmail.com


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