iio: Add names for function definition arguments.

As reported by checkpatch.pl add missing names for function definition
arguments.

Signed-off-by: Joe Simmons-Talbott <joetalbott@gmail.com>
Link: https://lore.kernel.org/r/20220731160120.4831-1-joetalbott@gmail.com


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