dt-bindings: display: sun4i-drm: Add compatible strings for A23 display

The A23's display pipeline is similar to the A33. Differences include:

  - Display backend supports larger layers, 8192x8192 instead of 2048x2048

  - TCON has DMA input

  - There is no SAT module packed in the display backend

Add compatible strings for the display pipeline and its components.

As the MIPI DSI output device is not officially documented, and there
are no A23 reference devices to test it, it is not covered by this
patch.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190125032314.20915-3-wens@csie.org

Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt

@@ -156,6 +156,7 @@ Required properties:
    * allwinner,sun6i-a31-tcon
    * allwinner,sun6i-a31s-tcon
    * allwinner,sun7i-a20-tcon
+   * allwinner,sun8i-a23-tcon
    * allwinner,sun8i-a33-tcon
    * allwinner,sun8i-a83t-tcon-lcd
    * allwinner,sun8i-a83t-tcon-tv
@@ -276,6 +277,7 @@ Required properties:
   - compatible: value must be one of:
     * allwinner,sun6i-a31-drc
     * allwinner,sun6i-a31s-drc
+    * allwinner,sun8i-a23-drc
     * allwinner,sun8i-a33-drc
     * allwinner,sun9i-a80-drc
   - reg: base address and size of the memory-mapped region.
@@ -303,6 +305,7 @@ Required properties:
     * allwinner,sun5i-a13-display-backend
     * allwinner,sun6i-a31-display-backend
     * allwinner,sun7i-a20-display-backend
+    * allwinner,sun8i-a23-display-backend
     * allwinner,sun8i-a33-display-backend
     * allwinner,sun9i-a80-display-backend
   - reg: base address and size of the memory-mapped region.
@@ -360,6 +363,7 @@ Required properties:
     * allwinner,sun5i-a13-display-frontend
     * allwinner,sun6i-a31-display-frontend
     * allwinner,sun7i-a20-display-frontend
+    * allwinner,sun8i-a23-display-frontend
     * allwinner,sun8i-a33-display-frontend
     * allwinner,sun9i-a80-display-frontend
   - reg: base address and size of the memory-mapped region.
@@ -419,6 +423,7 @@ Required properties:
     * allwinner,sun6i-a31-display-engine
     * allwinner,sun6i-a31s-display-engine
     * allwinner,sun7i-a20-display-engine
+    * allwinner,sun8i-a23-display-engine
     * allwinner,sun8i-a33-display-engine
     * allwinner,sun8i-a83t-display-engine
     * allwinner,sun8i-h3-display-engine