iio: ABI: add filter types for ad7173
Add new filter types used in the ad7173 driver to the IIO ABI
documentation. These chips have a few filter types that haven't been
seen before in other drivers.
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
authored by