dt-bindings: serial: amlogic,meson-uart: allow other serial properties

Reference common serial properties bindings to allow typical serial
properties:

  meson-axg-jethome-jethub-j100.dtb: serial@23000: 'bluetooth', 'uart-has-rtscts' do not match any of the regexes: 'pinctrl-[0-9]+'
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230124091602.44027-2-krzysztof.kozlowski@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/amlogic,meson-uart.yaml

@@ -19,6 +19,9 @@ description: |
   is active since power-on and does not need any clock gating and is usable
   as very early serial console.
 
+allOf:
+  - $ref: serial.yaml#
+
 properties:
   compatible:
     oneOf:
@@ -69,7 +72,7 @@ required:
   - clocks
   - clock-names
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |