iio: light: vcnl4000: add illuminance irq vcnl4040/4200

Add support to configure ambient light sensor interrupts and threshold
limits for vcnl4040 and vcnl4200. If an interrupt is detected an event
will be pushed to the event interface.

Signed-off-by: Astrid Rost <astrid.rost@axis.com>
Link: https://lore.kernel.org/r/20230613135025.2596641-6-astrid.rost@axis.com


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