dt-bindings: net: sun8i-emac: Add compatible for D1

The D1 SoC contains EMAC hardware which is compatible with the A64 EMAC.
Add the new compatible string, with the A64 as a fallback.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: David S. Miller <davem@davemloft.net>