dt-bindings: net: renesas,etheravb: Convert to json-schema

Convert the Renesas Ethernet AVB (EthernetAVB-IF) Device Tree binding
documentation to json-schema.

Add missing properties.
Update the example to match reality.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
---
v2:
  - Add Reviewed-by,
  - Replace "renesas,[rt]xc-delay-ps" by "[rt]x-internal-delay-ps", for
    which the base definition is imported from ethernet-controller.yaml.
2 files changed