iio: adc: ad_sigma_delta: add disable_one callback

iio: adc: ad_sigma_delta: add disable_one callback

Sigma delta ADCs with a sequencer need to disable the previously enabled
channel when reading using ad_sigma_delta_single_conversion(). This was
done manually in drivers for devices with sequencers.

This patch implements handling of single channel disabling after a
single conversion.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Dumitru Ceclan <dumitru.ceclan@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240607-ad4111-v7-3-97e3855900a0@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>