libcamera: pipeline: Remove explicit buffer handling

With the FrameBuffer interface in place there is no need for the Camera
to call into the specific pipelines allocation and freeing of buffers as
it no longer needs to be synchronized with buffer allocation by the
application.

Remove the function prototypes in the pipeline handler base class and
fold the functionality in the pipelines start() and stop() functions
where needed. A follow up patch will remove the now no-op
Camera::allocateBuffers() and Camera::freeBuffers().

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/libcamera/pipeline_handler.cpp

@@ -361,35 +361,6 @@ const ControlInfoMap &PipelineHandler::controls(Camera *camera)
  * helper.
  */
 
-/**
- * \fn PipelineHandler::allocateBuffers()
- * \brief Allocate buffers for a stream
- * \param[in] camera The camera the \a stream belongs to
- * \param[in] streams The set of streams to allocate buffers for
- *
- * This method allocates buffers internally in the pipeline handler for each
- * stream in the \a streams buffer set, and associates them with the stream's
- * buffer pool.
- *
- * The intended caller of this method is the Camera class.
- *
- * \return 0 on success or a negative error code otherwise
- */
-
-/**
- * \fn PipelineHandler::freeBuffers()
- * \brief Free all buffers associated with a stream
- * \param[in] camera The camera the \a stream belongs to
- * \param[in] streams The set of streams to free buffers from
- *
- * After a capture session has been stopped all buffers associated with each
- * stream shall be freed.
- *
- * The intended caller of this method is the Camera class.
- *
- * \return 0 on success or a negative error code otherwise
- */
-
 /**
  * \fn PipelineHandler::start()
  * \brief Start capturing from a group of streams