iio: adc: ad7768-1: Benefit from devm_clk_get_enabled() to simplify

Make use of devm_clk_get_enabled() to replace some code that effectively
open codes this new function.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220808204740.307667-2-u.kleine-koenig@pengutronix.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7768-1.c

@@ -539,13 +539,6 @@ static void ad7768_regulator_disable(void *data)
 	regulator_disable(st->vref);
 }
 
-static void ad7768_clk_disable(void *data)
-{
-	struct ad7768_state *st = data;
-
-	clk_disable_unprepare(st->mclk);
-}
-
 static int ad7768_set_channel_label(struct iio_dev *indio_dev,
 						int num_channels)
 {
@@ -600,18 +593,10 @@ static int ad7768_probe(struct spi_device *spi)
 	if (ret)
 		return ret;
 
-	st->mclk = devm_clk_get(&spi->dev, "mclk");
+	st->mclk = devm_clk_get_enabled(&spi->dev, "mclk");
 	if (IS_ERR(st->mclk))
 		return PTR_ERR(st->mclk);
 
-	ret = clk_prepare_enable(st->mclk);
-	if (ret < 0)
-		return ret;
-
-	ret = devm_add_action_or_reset(&spi->dev, ad7768_clk_disable, st);
-	if (ret)
-		return ret;
-
 	st->mclk_freq = clk_get_rate(st->mclk);
 
 	mutex_init(&st->lock);