arm64: dts: rockchip: Add GMAC nodes for RK3528

Rockchip RK3528 has two Ethernet controllers based on Synopsys DWC
Ethernet QoS IP.

Add device tree nodes for the two Ethernet controllers in RK3528.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Tested-by: Yao Zi <ziyao@disroot.org>
Link: https://lore.kernel.org/r/20250509202402.260038-2-jonas@kwiboo.se


Signed-off-by: Heiko Stuebner <heiko@sntech.de>