iio: amplifiers: ad8366 Fix whitespace issue

This removes the following checkpatch issue:
- ERROR: space prohibited before that ',' (ctx:WxW)

Signed-off-by: Franziska Naepelt <franziska.naepelt@gmail.com>
Link: https://lore.kernel.org/r/20230528104802.22011-1-franziska.naepelt@gmail.com


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