media: renesas: vsp1: Keep the DRM pipeline entities sorted

media: renesas: vsp1: Keep the DRM pipeline entities sorted

Some of the code that handles pipeline configuration assumes that
entities in a pipeline's entities list are sorted from sink to source.
To prepare for using that code with the DRM pipeline, insert the BRx
just before the WPF, and the RPFs at the head of the list.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>