Describe the interconnected FCPVD0, VSPD0, DU, and LVDS0 devices in the
R8A77980 device tree...

Based on the original (and large) patch by Vladimir Barinov.
Signed-off-by: NVladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>