dt-bindings: iio: adc: at91-sama5d2_adc: add id for temperature channel

Add ID for temperature channel of AT91 SAMA5D2 ADC.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220803102855.2191070-17-claudiu.beznea@microchip.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>