dt-bindings:iio:adc:atmel, sama9260-adc: conversion to yaml from at91_adc.txt

dt-bindings:iio:adc:atmel, sama9260-adc: conversion to yaml from at91_adc.txt

There are a few things we would do differently in an ADC binding if we
were starting from scratch but we are stuck with what we have (which
made sense back when this was written!)

We may be able to tighten up some elements of this binding in the future
by careful checking of what values properties can actually take.

Note the unusual sign off chain is representative of the path this patch
took.

Jonathan wrote the patch, which was then included in a series by
Alexandre and ultimately applied by Jonathan.

[Alexandre Belloni: add sama5d3, remove atmel,adc-res and atmel,adc-res-names]

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20201128222818.1910764-5-alexandre.belloni@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>