When starting the stream on a capture video device it is often needed to
queue all the allocated buffers. Add a helper method to do so, and
refactor the existing queueBuffer() method to make it clearer.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>