dt-bindings: iio: adc: ad7380: add pseudo-differential parts

Adding AD7383 and AD7384 compatible parts that are pseudo-differential.

Pseudo-differential require common mode voltage supplies, so add them
conditionally

Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240528-adding-new-ad738x-driver-v7-3-4cd70a4c12c8@baylibre.com


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