Add support for selecting REF+ and REF- inputs on all models.
 Add support for selecting ((AVDD1 − AVSS)/5) inputs
  on supported models.
Signed-off-by: Dumitru Ceclan <dumitru.ceclan@analog.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240607-ad4111-v7-6-97e3855900a0@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>