dt-bindings: iio: adc: at91-sama5d2: add compatible for sama7g5-adc

Add compatible for microchip,sama7g5-adc device.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Link: https://lore.kernel.org/r/20210901123013.329792-2-eugen.hristev@microchip.com


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