dt-bindings: display: panel: Add ilitek ili9341 panel bindings

Add documentation for "ilitek,ili9341" panel.
Signed-off-by: Dillon Min <dillon.minfei@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/lkml/1626853288-31223-2-git-send-email-dillon.minfei@gmail.com/Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1627098243-2742-2-git-send-email-dillon.minfei@gmail.com

Documentation/devicetree/bindings/display/panel/ilitek,ili9341.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/ilitek,ili9341.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Ilitek-9341 Display Panel
+
+maintainers:
+  - Dillon Min <dillon.minfei@gmail.com>
+
+description: |
+  Ilitek ILI9341 TFT panel driver with SPI control bus
+  This is a driver for 320x240 TFT panels, accepting a rgb input
+  streams with 16 bits or 18 bits.
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    items:
+      - enum:
+          # ili9341 240*320 Color on stm32f429-disco board
+        - st,sf-tc240t-9370-t
+      - const: ilitek,ili9341
+
+  reg: true
+
+  dc-gpios:
+    maxItems: 1
+    description: Display data/command selection (D/CX) of this DBI panel
+
+  spi-3wire: true
+
+  spi-max-frequency:
+    const: 10000000
+
+  port: true
+
+  vci-supply:
+    description: Analog voltage supply (2.5 .. 3.3V)
+
+  vddi-supply:
+    description: Voltage supply for interface logic (1.65 .. 3.3 V)
+
+  vddi-led-supply:
+    description: Voltage supply for the LED driver (1.65 .. 3.3 V)
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - dc-gpios
+  - port
+
+examples:
+  - |+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        panel: display@0 {
+                 compatible = "st,sf-tc240t-9370-t",
+                              "ilitek,ili9341";
+                 reg = <0>;
+                 spi-3wire;
+                 spi-max-frequency = <10000000>;
+                 dc-gpios = <&gpiod 13 0>;
+                 port {
+                         panel_in: endpoint {
+                           remote-endpoint = <&display_out>;
+                      };
+                 };
+             };
+        };
+...
+