dt-bindings: display: convert sony,acx565akm to DT Schema

v2:
  - drop use of spi-slave.yaml (Maxime)
  - add unevaluatedProperties (Maxime)
  - rename node in example to panel (Rob)
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200408195109.32692-27-sam@ravnborg.org

Documentation/devicetree/bindings/display/panel/sony,acx565akm.txt

-Sony ACX565AKM SDI Panel
-========================
-
-Required properties:
-- compatible: "sony,acx565akm"
-
-Optional properties:
-- label: a symbolic name for the panel
-- reset-gpios: panel reset gpio
-
-Required nodes:
-- Video port for SDI input
-
-Example
--------
-
-acx565akm@2 {
-	compatible = "sony,acx565akm";
-	spi-max-frequency = <6000000>;
-	reg = <2>;
-
-	label = "lcd";
-	reset-gpios = <&gpio3 26 GPIO_ACTIVE_HIGH>; /* 90 */
-
-	port {
-		lcd_in: endpoint {
-			remote-endpoint = <&sdi_out>;
-		};
-	};
-};

Documentation/devicetree/bindings/display/panel/sony,acx565akm.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/sony,acx565akm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sony ACX565AKM SDI Panel
+
+description: |
+  The panel must obey the rules for a SPI slave device as specified in
+  spi/spi-controller.yaml
+
+maintainers:
+  - Tomi Valkeinen <tomi.valkeinen@ti.com>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: sony,acx565akm
+
+  label: true
+  reset-gpios: true
+  port: true
+
+required:
+  - compatible
+  - port
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@2 {
+            compatible = "sony,acx565akm";
+            spi-max-frequency = <6000000>;
+            reg = <2>;
+
+            label = "lcd";
+            reset-gpios = <&gpio3 26 GPIO_ACTIVE_HIGH>; /* 90 */
+
+            port {
+                lcd_in: endpoint {
+                    remote-endpoint = <&sdi_out>;
+                };
+            };
+        };
+    };
+
+...