dt-bindings: display: vc4: dpi: Fix panel warning

The example used in the DPI binding before the conversion to YAML had a
simple-panel example that got carried over to the YAML binding.

However, that example doesn't match the simple-panel binding and results in
validation errors. Since it's only marginally helpful, let's remove that
part of the example entirely.

Fixes: 094536003e06 ("dt-bindings: display: Convert VC4 bindings to schemas")
Signed-off-by: Maxime Ripard <[e-mail]>
Acked-by: Sam Ravnborg <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

Documentation/devicetree/bindings/display/brcm,bcm2835-dpi.yaml

···
   - |
     #include <dt-bindings/clock/bcm2835.h>
 
-    panel: panel {
-        compatible = "ontat,yx700wv03", "simple-panel";
-
-        port {
-            panel_in: endpoint {
-                remote-endpoint = <&dpi_out>;
-            };
-        };
-    };
-
     dpi: dpi@7e208000 {
         compatible = "brcm,bcm2835-dpi";
         reg = <0x7e208000 0x8c>;