DSA switches can fall into one of two categories: switches where all ports
follow standard '(ethernet-)?port' properties, and switches that have
additional properties for the ports.
The scenario where DSA ports are all standardized can be handled by
swtiches with a reference to 'dsa.yaml#'.
The scenario where DSA ports require additional properties can reference
the new '$dsa.yaml#/$defs/base'. This will allow switches to reference
these base defitions of the DSA switch, but add additional properties under
the port nodes.
Suggested-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Colin Foster <colin.foster@xxxxxxxxxxxxxxxx>