iio: adc: ad7173: add support for ad4113

iio: adc: ad7173: add support for ad4113

This commit adds support for the AD4113 ADC.
The AD4113 is a low power, low noise, 16-bit, Σ-Δ analog-to-digital
converter (ADC) that integrates an analog front end (AFE) for four
fully differential or eight single-ended inputs.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Dumitru Ceclan <dumitru.ceclan@analog.com>
Link: https://patch.msgid.link/20240812-ad4113-v3-3-046e785dd253@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>