dt-bindings:iio:dac:maxim,ds4424 yaml conversion

Simple conversion of this straight forward binding.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Ismail H. Kose <ihkose@gmail.com>
Link: https://lore.kernel.org/r/20201031134110.724233-19-jic23@kernel.org


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