media: i2c: ad5820: Fix error path

Error path seems to be swaped. Fix the order and provide some meaningful
names.

Fixes: bee3d511

 ("[media] ad5820: Add driver for auto-focus coil")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>