ARM: dts: at91: sama7g5: add opps

Add OPPs for SAMA7G5 along with clock for CPU.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20220113144900.906370-9-claudiu.beznea@microchip.com