dt-bindings: mtd: Convert imx nand to json-schema

Convert the i.MX nand controller binding to DT schema format
using json-schema.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1596113004-15548-2-git-send-email-Anson.Huang@nxp.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/mtd/mxc-nand.txt

-* Freescale's mxc_nand
-
-Required properties:
-- compatible: "fsl,imxXX-nand"
-- reg: address range of the nfc block
-- interrupts: irq to be used
-- nand-bus-width: see nand-controller.yaml
-- nand-ecc-mode: see nand-controller.yaml
-- nand-on-flash-bbt: see nand-controller.yaml
-
-Example:
-
-	nand@d8000000 {
-		compatible = "fsl,imx27-nand";
-		reg = <0xd8000000 0x1000>;
-		interrupts = <29>;
-		nand-bus-width = <8>;
-		nand-ecc-mode = "hw";
-	};

Documentation/devicetree/bindings/mtd/mxc-nand.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mtd/mxc-nand.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title:  Freescale's mxc_nand binding
+
+maintainers:
+  - Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
+
+allOf:
+  - $ref: "nand-controller.yaml"
+
+properties:
+  compatible:
+    const: fsl,imx27-nand
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    nand-controller@d8000000 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        compatible = "fsl,imx27-nand";
+        reg = <0xd8000000 0x1000>;
+        interrupts = <29>;
+        nand-bus-width = <8>;
+        nand-ecc-mode = "hw";
+    };