iio: adc: dln2-adc: use new '.masklength' accessors

Make use of iio_get_masklength) and iio_for_each_active_channel() to
access '.masklength' so it can be annotated as __private when there
are no more direct users of it.
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20240718-dev-iio-masklength-private2-v1-2-8e12cd042906@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/dln2-adc.c

@@ -108,7 +108,7 @@ static void dln2_adc_update_demux(struct dln2_adc *dln2)
 	dln2->demux_count = 0;
 
 	/* Optimize all 8-channels case */
-	if (indio_dev->masklength &&
+	if (iio_get_masklength(indio_dev) &&
 	    (*indio_dev->active_scan_mask & 0xff) == 0xff) {
 		dln2_adc_add_demux(dln2, 0, 0, 16);
 		dln2->ts_pad_offset = 0;
@@ -117,9 +117,7 @@ static void dln2_adc_update_demux(struct dln2_adc *dln2)
 	}
 
 	/* Build demux table from fixed 8-channels to active_scan_mask */
-	for_each_set_bit(out_ind,
-			 indio_dev->active_scan_mask,
-			 indio_dev->masklength) {
+	iio_for_each_active_channel(indio_dev, out_ind) {
 		/* Handle timestamp separately */
 		if (out_ind == DLN2_ADC_MAX_CHANNELS)
 			break;
@@ -541,7 +539,7 @@ static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev)
 
 	/* Assign trigger channel based on first enabled channel */
 	trigger_chan = find_first_bit(indio_dev->active_scan_mask,
-				      indio_dev->masklength);
+				      iio_get_masklength(indio_dev));
 	if (trigger_chan < DLN2_ADC_MAX_CHANNELS) {
 		dln2->trigger_chan = trigger_chan;
 		ret = dln2_adc_set_chan_period(dln2, dln2->trigger_chan,