dt-bindings: arm: amlogic: add S4 based AQ222 bindings

Add bindings for the new Amlogic S4 SoC family,
and add binds the compatible for the Amlogic S4 Based AQ222 board.

S4 is an application processor designed for hybrid OTT/IP Set To
Box(STB) and high-end media box applications, with quad core Cortex-A35.
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20211221030014.434-1-xianwei.zhao@amlogic.com

Documentation/devicetree/bindings/arm/amlogic.yaml

@@ -183,6 +183,12 @@ properties:
               - amlogic,ad401
           - const: amlogic,a1
 
+      - description: Boards with the Amlogic Meson S4 S805X2 SoC
+        items:
+          - enum:
+              - amlogic,aq222
+          - const: amlogic,s4
+
 additionalProperties: true
 
 ...