iio: inkern: remove OF dependencies

Since all users of the OF dependendent API are now converted to use the
firmware agnostic alternative, we can drop OF dependencies from the IIO
in kernel interface.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220715122903.332535-15-nuno.sa@analog.com


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