dt-bindings: phy: rockchip: rk3588 has two reset lines

The RK3588 has two reset lines for the combphy. One for the
APB interface and one for the actual PHY.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>