[media] uvcvideo: Return all buffers to vb2 at stream stop and start failure

videobuf2 requires drivers to give back ownership of all queue buffers
in the stop_streaming operation, as well as in the start_streaming
operation in case of failure. Mark all queued buffers as done in the
error or queued state.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>