arm64: dts: rockchip: Enable PCIe 2 on SOQuartz CM4IO

This patch enables the PCIe2 on the CM4IO board when paired with
a SOQuartz CM4 System-on-Module board. combphy2 also needs to be
enabled in this case to make the PHY work for this.

Signed-off-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
Link: https://lore.kernel.org/r/20221112160404.70868-5-frattaroli.nicolas@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>