dt-bindings: net: Fix unevaluatedProperties warnings in examples

The 'unevaluatedProperties' schema checks is not fully working and doesn't
catch some cases where there's a $ref to another schema. A fix is pending,
but results in new warnings in examples. Fix the warnings by removing
spurious properties or adding missing properties to the schema.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20220526014149.2872762-1-robh@kernel.org