dt-bindings: reset: Convert i.MX reset to json-schema

Convert the i.MX reset binding to DT schema format using json-schema.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>