dt-bindings: net: Convert UniPhier AVE4 controller to json-schema

Convert the UniPhier AVE4 controller binding to DT schema format.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>