ARM: dts: at91: sama7g5: add thermal zones node

Add thermal zones node with its associated trips and cooling-maps.
It uses CPUFreq as cooling device for temperatures in the interval
[90, 100) degrees Celsius and describe the temperature of 100 degrees
Celsius as critical temperature. System will be is shutting down when
reaching critical temperature.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221026124114.985876-7-claudiu.beznea@microchip.com