regulator:pfuze100: fix build warning and correct the binding doc

fix building warning and correct the binding doc
Signed-off-by: Robin Gong <b38343@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

Documentation/devicetree/bindings/regulator/pfuze100.txt

@@ -3,6 +3,8 @@ PFUZE100 family of regulators
 Required properties:
 - compatible: "fsl,pfuze100"
 - reg: I2C slave address
+
+Required child node:
 - regulators: This is the list of child nodes that specify the regulator
   initialization data for defined regulators. Please refer to below doc
   Documentation/devicetree/bindings/regulator/regulator.txt.

drivers/regulator/pfuze100-regulator.c

@@ -295,7 +295,7 @@ static inline struct device_node *match_of_node(int index)
 #else
 static int pfuze_parse_regulators_dt(struct pfuze_chip *chip)
 {
-	return NULL;
+	return 0;
 }
 
 static inline struct regulator_init_data *match_init_data(int index)