dt-bindings: arm: amlogic: add S6 support

Document the new S6 SoC/board device tree bindings.

Amlogic S6 is an advanced application processor designed for
hybrid OTT/IP Set Top Box and high-end media box applications.

Signed-off-by: Xianwei Zhao <[email protected]>
Acked-by: Rob Herring (Arm) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Neil Armstrong <[email protected]>

Author: Xianwei Zhao

Documentation/devicetree/bindings/arm/amlogic.yaml

@@ -237,6 +237,12 @@ properties:
               - amlogic,aq222
           - const: amlogic,s4
 
+      - description: Boards with the Amlogic S6 S905X5 SoC
+        items:
+          - enum:
+              - amlogic,bl209
+          - const: amlogic,s6
+
       - description: Boards with the Amlogic T7 A311D2 SoC
         items:
           - enum: