iio: imu: adis: Remove documented not used elements

This patch removes elements from adis.h that are documented
but not used anymore.

Signed-off-by: Robert Budai <robert.budai@analog.com>
Link: https://patch.msgid.link/20241125133520.24328-2-robert.budai@analog.com


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