media: dt-bindings: media: ov772x: Make bus-type mandatory

In order to establish required properties based on the selected
bus type, make the 'bus-type' property mandatory. As this change
documents an endpoint property, also document the 'remote-endpoint'
one now that the 'endpoint' schema has been expanded.

Binary compatibility with existing DTB is kept as the driver does not
enforce the property to be present, and shall fall-back to default
parallel bus configuration, which was the only supported bus type, if
the property is not specified.

Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/devicetree/bindings/media/i2c/ovti,ov772x.yaml

@@ -41,6 +41,21 @@ properties:
     description: |
       Video output port. See ../video-interfaces.txt.
 
+    properties:
+      endpoint:
+        type: object
+
+        properties:
+          bus-type:
+            enum: [5, 6]
+
+        required:
+          - bus-type
+
+        unevaluatedProperties: false
+
+    additionalProperties: false
+
 required:
   - compatible
   - reg
@@ -65,6 +80,7 @@ examples:
 
             port {
                 ov772x_0: endpoint {
+                    bus-type = <5>;
                     remote-endpoint = <&vcap1_in0>;
                 };
             };