drivers: soc: atmel: Add basic support for new sama5d2 SiPs

Add basic support for new sama5d2 System in a Package chips.

Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>
[claudiu.beznea@microchip.com: use MiB instead of MB]
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>