ARM: dts: rockchip: change rv1108 gmac nodename

The rv1108 gmac node is checked with rockchip-dwmac.yaml,
snps,dwmac.yaml and ethernet-controller.yaml.
The nodename should have a pattern: "^ethernet(@.*)?$",
so change to nodename.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20210828114240.12231-1-jbx6244@gmail.com


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