arm64: dts: rockchip: fix rtl8211e nodename for rk3399-nanopi4

arm64: dts: rockchip: fix rtl8211e nodename for rk3399-nanopi4

A test with the command below gives these errors:

arch/arm64/boot/dts/rockchip/rk3399-nanopc-t4.dt.yaml: phy@1:
'#phy-cells' is a required property
arch/arm64/boot/dts/rockchip/rk3399-nanopi-m4.dt.yaml: phy@1:
'#phy-cells' is a required property
arch/arm64/boot/dts/rockchip/rk3399-nanopi-neo4.dt.yaml: phy@1:
'#phy-cells' is a required property

The rtl8211e node is used by a phy-handle.
The parent node is compatible with "snps,dwmac-mdio",
so change nodename to 'ethernet-phy', for which '#phy-cells'
is not a required property.

make ARCH=arm64 dtbs_check
DT_SCHEMA_FILES=~/.local/lib/python3.5/site-packages/dtschema/schemas/
phy/phy-provider.yaml

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20200321215423.12176-3-jbx6244@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>