iio: dac: ad3552r: Use device_for_each_child_node_scoped()

iio: dac: ad3552r: Use device_for_each_child_node_scoped()

Switching to the _scoped() version removes the need for manual
calling of fwnode_handle_put() in the paths where the code
exits the loop early. In this case that's all in error paths.

Removing the goto err; statements also allows more extensive use of
dev_err_probe() further simplifying the code.

Cc: Mihail Chindris <mihail.chindris@analog.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240330185305.1319844-8-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>