dt-bindings: fix simple-framebuffer example

Now that dt-extract-example gained support for using root nodes
in examples, update the example for the simple-frambuffer binding to use it.

This gives us a better example and kill a long standing warning:

simple-framebuffer.example.dts:23.16-39.11:
Warning (chosen_node_is_root): /example-0/chosen: chosen node must be at root node

Note: To get the update dt-extract-example execute:
pip3 install git+https://github.com/devicetree-org/dt-schema.git@master --upgrade

v2:
  - fix spelling of framebuffer (Geert)
  - drop stdout-path (Rob)
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-fbdev@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200704143544.789345-2-sam@ravnborg.org

Documentation/devicetree/bindings/display/simple-framebuffer.yaml

@@ -152,14 +152,15 @@ additionalProperties: false
 
 examples:
   - |
-    aliases {
-      display0 = &lcdc0;
-    };
+    / {
+        compatible = "foo";
+        model = "foo";
+        #address-cells = <1>;
+        #size-cells = <1>;
 
         chosen {
             #address-cells = <1>;
             #size-cells = <1>;
-      stdout-path = "display0";
             framebuffer0: framebuffer@1d385000 {
                 compatible = "allwinner,simple-framebuffer", "simple-framebuffer";
                 allwinner,pipeline = "de_be0-lcd0";
@@ -173,7 +174,6 @@ examples:
                 display = <&lcdc0>;
             };
         };
-
-    lcdc0: lcdc { };
+    };
 
 ...