dt-bindings: iio: accel: kxcjk1013: Add device tree binding documentation

Document device tree bindings for Kionix KXCJK-1013 Accelerometer driver.
Signed-off-by: Robert Yang <decatf@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/accel/kionix,kxcjk1013.txt

+Kionix KXCJK-1013 Accelerometer device tree bindings
+
+Required properties:
+
+- compatible: Must be one of:
+    "kionix,kxcjk1013"
+    "kionix,kxcj91008"
+    "kionix,kxtj21009"
+    "kionix,kxtf9"
+ - reg: i2c slave address
+
+Example:
+
+kxtf9@f {
+	compatible = "kionix,kxtf9";
+	reg = <0x0F>;
+};