dt-bindings: net: mscc,vsc7514-switch: utilize generic ethernet-switch.yaml

Several bindings for ethernet switches are available for non-dsa switches
by way of ethernet-switch.yaml. Remove these duplicate entries and utilize
the common bindings for the VSC7514.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>