watchdog: mtk_wdt: Add support for MT6795 Helio X10 watchdog and toprgu

Add support for the toprgu reset controller and watchdog for the
MediaTek MT6795 SoC.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Co-developed-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221005113517.70628-6-angelogioacchino.delregno@collabora.com


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