iio: light: apds9306: Improve apds9306_write_event_config()

Simplify event configuration flow.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Link: https://lore.kernel.org/all/20240310124237.52fa8a56@jic23-huawei/


Signed-off-by: Subhajit Ghosh <subhajit.ghosh@tweaklogic.com>
Link: https://lore.kernel.org/r/20240405104641.29478-1-subhajit.ghosh@tweaklogic.com


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