dt-bindings: net: ethernet-switch: Make "#address-cells/#size-cells" required

dt-bindings: net: ethernet-switch: Make "#address-cells/#size-cells" required

The schema doesn't allow for a single (unaddressed) ethernet port node
nor does a single port switch make much sense. So if there's always
multiple child nodes, "#address-cells" and "#size-cells" should be
required.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230404204213.635773-1-robh@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>