iio: adc: max1241: simplify using devm_regulator_get_enable()

Drop open-coded pattern: 'devm_regulator_get(), regulator_enable(),
add_action_or_reset(regulator_disable)' and use the
devm_regulator_get_enable() and drop the pointer to the regulator.
This simplifies code and makes it less tempting to add manual control
for the regulator which is also controlled by devm.

Signed-off-by: Matti Vaittinen <[e-mail]>
Acked-by: Alexandru Lazar <[e-mail]>
Link: https://lore.kernel.org/r/7c759b[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/max1241.c

···
 struct max1241 {
 	struct spi_device *spi;
 	struct mutex lock;
-	struct regulator *vdd;
 	struct regulator *vref;
 	struct gpio_desc *shutdown;
 
···
 	.read_raw = max1241_read_raw,
 };
 
-static void max1241_disable_vdd_action(void *data)
-{
-	struct max1241 *adc = data;
-	struct device *dev = &adc->spi->dev;
-	int err;
-
-	err = regulator_disable(adc->vdd);
-	if (err)
-		dev_err(dev, "could not disable vdd regulator.\n");
-}
-
 static void max1241_disable_vref_action(void *data)
 {
 	struct max1241 *adc = data;
···
 	adc->spi = spi;
 	mutex_init(&adc->lock);
 
-	adc->vdd = devm_regulator_get(dev, "vdd");
-	if (IS_ERR(adc->vdd))
-		return dev_err_probe(dev, PTR_ERR(adc->vdd),
-				     "failed to get vdd regulator\n");
-
-	ret = regulator_enable(adc->vdd);
+	ret = devm_regulator_get_enable(dev, "vdd");
 	if (ret)
-		return ret;
-
-	ret = devm_add_action_or_reset(dev, max1241_disable_vdd_action, adc);
-	if (ret) {
-		dev_err(dev, "could not set up vdd regulator cleanup action\n");
-		return ret;
-	}
+		return dev_err_probe(dev, ret,
+				     "failed to get/enable vdd regulator\n");
 
 	adc->vref = devm_regulator_get(dev, "vref");
 	if (IS_ERR(adc->vref))