The graph schema doesn't allow custom properties on endpoint nodes for
'#/properties/port' and '#/$defs/port-base' should be used instead. This
doesn't matter until 'unevaluatedProperties' support is implemented.

Cc: Dave Stevenson <dave.stevenson@raspberrypi.com>
Cc: Jacopo Mondi <jacopo@jmondi.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: "Paul J. Murphy" <paul.j.murphy@intel.com>
Cc: Daniele Alessandrelli <daniele.alessandrelli@intel.com>
Cc: linux-media@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Daniele Alessandrelli <daniele.alessandrelli@intel.com>
Link: https://lore.kernel.org/r/20210820001457.1705142-1-robh@kernel.org