iio: adc: xilinx-ams: use device_* to iterate over device child nodes

Use `device_for_each_child_node_scoped()` in `ams_parse_firmware()`
to explicitly state device child node access, and simplify the child
node handling as it is not required outside the loop.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Link: https://patch.msgid.link/20240820-device_child_node_access-v3-1-1ee09bdedb9e@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: javiercarrascocruz

drivers/iio/adc/xilinx-ams.c

@@ -1275,7 +1275,6 @@ static int ams_parse_firmware(struct iio_dev *indio_dev)
 	struct ams *ams = iio_priv(indio_dev);
 	struct iio_chan_spec *ams_channels, *dev_channels;
 	struct device *dev = indio_dev->dev.parent;
-	struct fwnode_handle *child = NULL;
 	struct fwnode_handle *fwnode = dev_fwnode(dev);
 	size_t ams_size;
 	int ret, ch_cnt = 0, i, rising_off, falling_off;
@@ -1297,16 +1296,12 @@ static int ams_parse_firmware(struct iio_dev *indio_dev)
 		num_channels += ret;
 	}
 
-	fwnode_for_each_child_node(fwnode, child) {
-		if (fwnode_device_is_available(child)) {
-			ret = ams_init_module(indio_dev, child, ams_channels + num_channels);
-			if (ret < 0) {
-				fwnode_handle_put(child);
-				return ret;
-			}
+	device_for_each_child_node_scoped(dev, child) {
+		ret = ams_init_module(indio_dev, child, ams_channels + num_channels);
+		if (ret < 0)
+			return ret;
 
-			num_channels += ret;
-		}
+		num_channels += ret;
 	}
 
 	for (i = 0; i < num_channels; i++) {