iio: adc: ad7124: Use separate structures rather than array for chip info

iio: adc: ad7124: Use separate structures rather than array for chip info

Change the ad7124 driver to use individual chip info structures instead
of an array. This reduces the verbosity of the code. Also, the data is
now const as it should have been in the first place.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/20250628-iio-const-data-5-v1-1-9e56c2f77979@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>