dt-bindings: display: panel: visionox,vtdr6130: add missing reg property

Add missing reg property and update example to add dsi top node.

Fixes: ef85db91 ("dt-bindings: display: panel: document the Visionox VTDR6130 AMOLED DSI Panel")
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230207-topic-sm8550-upstream-vtdr6130-bindings-fix-v1-1-0ba2323420c5@linaro.org

Documentation/devicetree/bindings/display/panel/visionox,vtdr6130.yaml

@@ -16,6 +16,10 @@ properties:
   compatible:
     const: visionox,vtdr6130
 
+  reg:
+    maxItems: 1
+    description: DSI virtual channel
+
   vddio-supply: true
   vci-supply: true
   vdd-supply: true
@@ -26,6 +30,7 @@ additionalProperties: false
 
 required:
   - compatible
+  - reg
   - vddio-supply
   - vci-supply
   - vdd-supply
@@ -35,8 +40,12 @@ required:
 examples:
   - |
     #include <dt-bindings/gpio/gpio.h>
-    panel {
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        panel@0 {
             compatible = "visionox,vtdr6130";
+            reg = <0>;
 
             vddio-supply = <&vreg_l12b_1p8>;
             vci-supply = <&vreg_l13b_3p0>;
@@ -50,4 +59,5 @@ examples:
                 };
             };
         };
+    };
 ...