dt-bindings: hwmon: Document the IBM CCF power supply version 1

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/ibm,cffps1.txt

+Device-tree bindings for IBM Common Form Factor Power Supply Version 1
+----------------------------------------------------------------------
+
+Required properties:
+ - compatible = "ibm,cffps1";
+ - reg = < I2C bus address >;		: Address of the power supply on the
+					  I2C bus.
+
+Example:
+
+    i2c-bus@100 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        #interrupt-cells = <1>;
+        < more properties >
+
+        power-supply@68 {
+            compatible = "ibm,cffps1";
+            reg = <0x68>;
+        };
+    };