iio: adc: xilinx-xadc-core: 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/20240726-dev-iio-masklength-private3-v1-20-82913fc0fb87@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/xilinx-xadc-core.c

@@ -628,7 +628,7 @@ static int xadc_update_scan_mode(struct iio_dev *indio_dev,
 	size_t n;
 	void *data;
 
-	n = bitmap_weight(mask, indio_dev->masklength);
+	n = bitmap_weight(mask, iio_get_masklength(indio_dev));
 
 	data = devm_krealloc_array(indio_dev->dev.parent, xadc->data,
 				   n, sizeof(*xadc->data), GFP_KERNEL);
@@ -681,8 +681,7 @@ static irqreturn_t xadc_trigger_handler(int irq, void *p)
 		goto out;
 
 	j = 0;
-	for_each_set_bit(i, indio_dev->active_scan_mask,
-		indio_dev->masklength) {
+	iio_for_each_active_channel(indio_dev, i) {
 		chan = xadc_scan_index_to_channel(i);
 		xadc_read_adc_reg(xadc, chan, &xadc->data[j]);
 		j++;