dt-bindings: net: mscc,vsc7514-switch: Simplify DSA and switch references

The mscc,vsc7514-switch schema doesn't add any custom port properties,
so it can just reference ethernet-switch.yaml#/$defs/base and
dsa.yaml#/$defs/ethernet-ports instead of the base file and can skip
defining port nodes.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20231016-dt-net-cleanups-v1-7-a525a090b444@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>