drivers: soc: atmel: add support for sama7g5

Add support for SAMA7G5 SoCs.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/1611318097-8970-8-git-send-email-claudiu.beznea@microchip.com