libcamera: camera_lens: Add function to fetch subdev controls

Add a function to the CameraLens class to fetch the V4L2 controls
for its V4L2 subdev

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2 files changed