ARM: at91: add new SoC sama7g5

Add new SoC from at91 family : sama7g5

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
[claudiu.beznea@microchip.com: Select PLL, generic clock and UTMI support, add PM configs]
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20210409113116.482199-1-eugen.hristev@microchip.com
Link: https://lore.kernel.org/r/20210719080317.1045832-2-claudiu.beznea@microchip.com