dt-bindings: arm: amlogic: add C3 bindings

Document the new C3 SoC/board device tree bindings.

C3 is an advanced edge AI processor designed for smart IP camera
applications, which does not belong to Meson series.

Therefore, modify the title field accordingly.

Signed-off-by: Kelvin Zhang <kelvin.zhang@amlogic.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230407102704.1055152-1-kelvin.zhang@amlogic.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

Documentation/devicetree/bindings/arm/amlogic.yaml

@@ -4,7 +4,7 @@
 $id: http://devicetree.org/schemas/arm/amlogic.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Amlogic MesonX
+title: Amlogic SoC based Platforms
 
 maintainers:
   - Kevin Hilman <khilman@baylibre.com>
@@ -205,6 +205,13 @@ properties:
               - amlogic,ad401
           - const: amlogic,a1
 
+      - description: Boards with the Amlogic C3 C302X/C308L SoC
+        items:
+          - enum:
+              - amlogic,aw409
+              - amlogic,aw419
+          - const: amlogic,c3
+
       - description: Boards with the Amlogic Meson S4 S805X2 SoC
         items:
           - enum: