ARM: dts: sun8i: V3/V3s/S3/S3L: add Ethernet support

The Allwinner V3/V3s/S3L/SoChip S3 Ethernet MAC and internal PHY is quite
similar to the ones on Allwinner H3, except for V3s the external MII is
not wired out.

Add ethernet support to V3/V3s/S3/S3L.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20200923005709.147966-2-icenowy@aosc.io