ipa: Switch to FrameBuffer interface

Switch the IPA interfaces and implementations to use the Framebuffer
interface.

- The IPA interface is switched to use the simpler FrameBuffer::Plane
  container when carrying dmabuf descriptions (fd and length) over the
  pipeline/IPA boundary.

- The RkISP1 IPA implementation takes advantage of the new simpler and
  safer (better control over file descriptors) FrameBuffer interface.

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

src/libcamera/ipa_interface.cpp

@@ -334,11 +334,10 @@ namespace libcamera {
  */
 
 /**
- * \var IPABuffer::memory
- * \brief The buffer memory description
+ * \var IPABuffer::planes
+ * \brief The buffer planes description
  *
- * The memory field stores the dmabuf handle and size for each plane of the
- * buffer.
+ * Stores the dmabuf handle and length for each plane of the buffer.
  */
 
 /**