dt-bindings: media: renesas,drif: Use graph schema

Convert the renesas,drif binding schema to use the graph schema. The
binding referred to video-interfaces.txt, but it doesn't actually use any
properties from it as 'sync-active' is a custom property. As 'sync-active'
is custom, it needs a type definition.

Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Ramesh Shanmugasundaram <rashanmu@gmail.com>
Cc: linux-media@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Link: https://lore.kernel.org/r/20210510203514.603471-1-robh@kernel.org