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.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>