dt-bindings: i2c: Convert mxs i2c to json-schema

Convert the MXS I2C binding to DT schema format using json-schema

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1592279454-32551-1-git-send-email-Anson.Huang@nxp.com


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