iio: adc: ad7192: Use bitfield access macros

Include bitfield.h and update driver to use bitfield access macros GENMASK,
FIELD_PREP and FIELD_GET.

Remove old macros in favor of using FIELD_PREP and masks.

Change %d to %ld to match the type of FIELD_GET().

Signed-off-by: Alisa-Dariana Roman <alisa.roman@analog.com>
Link: https://lore.kernel.org/r/20230924215148.102491-2-alisadariana@gmail.com


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