The IPU3 pipeline handler that does not support receiving an empty list of roles at generateConfiguration() time. This contradicts the camera API which allows application to generate empty CameraConfiguration to be later manually filled. Fix this by returning an empty CameraConfiguration if the list of requested roles is empty. While at it, align the style with the other pipeline handlers. Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>