Now that we have a graph schema, rework the media related schemas to
use it. Mostly this is adding a reference to graph.yaml and dropping
duplicate parts from schemas.

Cc: Maxime Ripard <mripard@kernel.org>
Cc: Jacopo Mondi <jacopo@jmondi.org>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>