power: reset: at91-reset: add sdhwc support for sam9x7 SoC

Add shutdown controller support for SAM9X7 SoC.

Signed-off-by: Varshini Rajendran <varshini.rajendran@microchip.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Link: https://lore.kernel.org/r/20241010120414.92993-1-varshini.rajendran@microchip.com


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>