dt-bindings: i2c: Convert UniPhier I2C controller to json-schema

Convert the UniPhier I2C controller (FIFO-less) binding to DT schema
format.

There are two types of I2C controllers used on the UniPhier platform.
This is the legacy one without FIFO support, which is used on the
sLD8 SoC or older.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/i2c/i2c-uniphier.txt

-UniPhier I2C controller (FIFO-less)
-
-Required properties:
-- compatible: should be "socionext,uniphier-i2c".
-- #address-cells: should be 1.
-- #size-cells: should be 0.
-- reg: offset and length of the register set for the device.
-- interrupts: a single interrupt specifier.
-- clocks: phandle to the input clock.
-
-Optional properties:
-- clock-frequency: desired I2C bus frequency in Hz.  The maximum supported
-  value is 400000.  Defaults to 100000 if not specified.
-
-Examples:
-
-	i2c0: i2c@58400000 {
-		compatible = "socionext,uniphier-i2c";
-		reg = <0x58400000 0x40>;
-		#address-cells = <1>;
-		#size-cells = <0>;
-		interrupts = <0 41 1>;
-		clocks = <&i2c_clk>;
-		clock-frequency = <100000>;
-	};

Documentation/devicetree/bindings/i2c/socionext,uniphier-i2c.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/socionext,uniphier-i2c.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: UniPhier I2C controller (FIFO-less)
+
+maintainers:
+  - Masahiro Yamada <yamada.masahiro@socionext.com>
+
+allOf:
+  - $ref: /schemas/i2c/i2c-controller.yaml#
+
+properties:
+  compatible:
+    const: socionext,uniphier-i2c
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-frequency:
+    minimum: 100000
+    maximum: 400000
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+  - interrupts
+  - clocks
+
+examples:
+  - |
+    i2c0: i2c@58400000 {
+        compatible = "socionext,uniphier-i2c";
+        reg = <0x58400000 0x40>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        interrupts = <0 41 1>;
+        clocks = <&i2c_clk>;
+        clock-frequency = <100000>;
+    };