dt-bindings: display: panel: Add WL-355608-A8 panel

The WL-355608-A8 is a 3.5" 640x480@60Hz RGB LCD display used in a
number of handheld gaming devices made by Anbernic. By consensus a
vendor prefix is not provided as the panel OEM is unknown.

Add a device tree binding for the panel.
Signed-off-by: Ryan Walklin <ryan@testtoast.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240530211415.44201-3-ryan@testtoast.comSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240530211415.44201-3-ryan@testtoast.com

Documentation/devicetree/bindings/display/panel/wl-355608-a8.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/wl-355608-a8.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: WL-355608-A8 3.5" (640x480 pixels) 24-bit IPS LCD panel
+
+maintainers:
+  - Ryan Walklin <ryan@testtoast.com>
+
+allOf:
+  - $ref: panel-common.yaml#
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    const: wl-355608-a8
+
+  reg:
+    maxItems: 1
+
+  spi-3wire: true
+
+required:
+  - compatible
+  - reg
+  - port
+  - power-supply
+  - reset-gpios
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "wl-355608-a8";
+            reg = <0>;
+
+            spi-3wire;
+            spi-max-frequency = <3125000>;
+
+            reset-gpios = <&pio 8 14 GPIO_ACTIVE_LOW>; // PI14
+
+            backlight = <&backlight>;
+            power-supply = <&reg_lcd>;
+
+            port {
+                endpoint {
+                    remote-endpoint = <&tcon_lcd0_out_lcd>;
+                };
+            };
+        };
+    };