mfd: arizona: Update DT binding to support LDO1 init_data

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/devicetree/bindings/mfd/arizona.txt

@@ -42,6 +42,14 @@ Optional properties:
     the chip default will be used.  If present exactly five values must
     be specified.
 
+  - DCVDD-supply : Power supply, only needs to be specified if DCVDD is being
+    externally supplied. As covered in
+    Documentation/devicetree/bindings/regulator/regulator.txt
+
+Optional subnodes:
+  - ldo1 : Initial data for the LDO1 regulator, as covered in
+    Documentation/devicetree/bindings/regulator/regulator.txt
+
 Example:
 
 codec: wm5102@1a {