dt-bindings: iio: light: isl76682: Document ISL76682

The ISL76682 is very basic ALS which only supports ALS or IR mode
in four ranges, 1k/4k/16k/64k LUX. There is no IRQ support or any
other fancy functionality. Document it as trivial device.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20231127212726.77707-1-marex@denx.de


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