iio: light: noa1305: Make integration time configurable

Add another attribute which is the integration time. Report available
integration time settings, support read of integration time currently
configured in hardware, and support configuration of integration time
into hardware.

Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patch.msgid.link/20240715183120.143417-5-marex@denx.de


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