iio: dac: ad5791: Include chip_info in device match tables

Include a chip info struct in device SPI and device OF match tables to
provide channel definitions for each particular ADC model and drop
device enum.

Suggested-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Axel Haslam <ahaslam@baylibre.com>
Link: https://patch.msgid.link/20241031071746.848694-4-ahaslam@baylibre.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>