regulator fixed: Do not report enumaratable voltages if there are none

If used as a dummy voltage provider the fixed regulator should
not set n_voltages to make the core accept the device.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/fixed.c

@@ -192,7 +192,9 @@ static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
 	drvdata->desc.type = REGULATOR_VOLTAGE;
 	drvdata->desc.owner = THIS_MODULE;
 	drvdata->desc.ops = &fixed_voltage_ops;
-	drvdata->desc.n_voltages = 1;
+
+	if (config->microvolts)
+		drvdata->desc.n_voltages = 1;
 
 	drvdata->microvolts = config->microvolts;
 	drvdata->gpio = config->gpio;