watchdog: mtk_wdt: Add reset_by_toprgu support

In some cases, the MediaTek watchdog requires the TOPRGU to reset
timer after system resets.

Provide a reset_by_toprgu parameter for configuration.

Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230117014023.2993-3-allen-kh.cheng@mediatek.com


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