arm64: dts: rockchip: drop unused LED mode property from rk3328-roc-cc

GPIO LEDs do not have a 'mode' property:

  rockchip/rk3328-roc-pc.dtb: leds: led-0: Unevaluated properties are not allowed ('mode' was unexpected)

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221125144135.477144-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Heiko Stuebner <heiko@sntech.de>