dt-bindings: gpio: Convert vf610 to json-schema

Convert the vf610 gpio binding to DT schema format using json-schema.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1597218741-24899-1-git-send-email-Anson.Huang@nxp.com


Signed-off-by: Rob Herring <robh@kernel.org>