dt-bindings:iio:adc:remove atmel, adc-res and atmel, adc-res-names

Remove atmel,adc-res and atmel,adc-res-names as they are not necessary and
are handled by the driver. Also add sama5d3 to the list of possible chips.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Rob Herring <robh+dt@kernel.org>
Link: https://lore.kernel.org/r/20201128222818.1910764-4-alexandre.belloni@bootlin.com


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