arm64: dts: rockchip: Add ethernet0 alias to the dts for RK3588(S) boards

Add ethernet0 alias to the board dts files for a few supported RK3588 and
RK3588S boards that had it missing.

Signed-off-by: Dragan Simic <dsimic@manjaro.org>
Link: https://lore.kernel.org/r/9af2026bf8a5538aff627381289cb06f2fab4263.1702368023.git.dsimic@manjaro.org


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