regulator: gpio: Don't require a regulator-type property

Since essentially all GPIO controlled regulators are voltage regulators
make the regulator-type property optional, defaulting to voltage.
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/regulator/gpio-regulator.c

@@ -203,16 +203,14 @@ of_get_gpio_regulator_config(struct device *dev, struct device_node *np)
 	}
 	config->nr_states = i;
 
+	config->type = REGULATOR_VOLTAGE;
 	ret = of_property_read_string(np, "regulator-type", &regtype);
-	if (ret < 0) {
-		dev_err(dev, "Missing 'regulator-type' property\n");
-		return ERR_PTR(-EINVAL);
-	}
-
+	if (ret >= 0) {
 		if (!strncmp("voltage", regtype, 7))
 			config->type = REGULATOR_VOLTAGE;
 		else if (!strncmp("current", regtype, 7))
 			config->type = REGULATOR_CURRENT;
+	}
 
 	return config;
 }