dt-bindings: phy: rockchip: Add rk3588 compatible

RK3568 Naneng Combo Phy driver can support RK3588 with the additional
clocks and initial configuration, so add the compatible line.

Signed-off-by: Lucas Tanure <lucas.tanure@collabora.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230314135555.44162-3-lucas.tanure@collabora.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>