arm64: dts: rockchip: add PCIe2 network controller to rk3588-evb1

The RK3588 EVB1 has a second network card, which is connected
via PCIe2. This adds support for that.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20230918141327.131108-2-sebastian.reichel@collabora.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>