dt-bindings: iio: adc: ad7380: add adaq4381-4 compatible parts

adaq4381-4 is the 14 bits version of adaq4380-1 chip. Add support for
it.

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250226-ad7380-add-adaq4381-4-support-v1-2-f350ab872d37@baylibre.com


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