iio:proximity:sx9360: Add dt-binding support

Add support to configure sx9360 from dt-binding, to match device
hardware setup.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20220101203800.290387-4-gwendal@chromium.org


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