power: reset: at91-reset: add support for sam9x60 SoC

Add support for additional reset causes and the proper compatibility
string for sam9x60 SoC. The restart function is the same as the samx7.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>