iio: adc: meson: move meson_sar_adc_set_chan7_mux routine upper

meson_sar_adc_set_chan7_mux is a basic func() for writing single register,
defined as static. Moved it up so it could be used in more places.
Signed-off-by: George Stark <GNStark@sberdevices.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230714114010.293440-4-gnstark@sberdevices.ruSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/meson_saradc.c

@@ -336,6 +336,19 @@ static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
 					       1, 10000);
 }
 
+static void meson_sar_adc_set_chan7_mux(struct iio_dev *indio_dev,
+					enum meson_sar_adc_chan7_mux_sel sel)
+{
+	struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
+	u32 regval;
+
+	regval = FIELD_PREP(MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, sel);
+	regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
+			   MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, regval);
+
+	usleep_range(10, 20);
+}
+
 static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
 					 const struct iio_chan_spec *chan,
 					 int *val)
@@ -432,19 +445,6 @@ static void meson_sar_adc_enable_channel(struct iio_dev *indio_dev,
 	}
 }
 
-static void meson_sar_adc_set_chan7_mux(struct iio_dev *indio_dev,
-					enum meson_sar_adc_chan7_mux_sel sel)
-{
-	struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
-	u32 regval;
-
-	regval = FIELD_PREP(MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, sel);
-	regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
-			   MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, regval);
-
-	usleep_range(10, 20);
-}
-
 static void meson_sar_adc_start_sample_engine(struct iio_dev *indio_dev)
 {
 	struct meson_sar_adc_priv *priv = iio_priv(indio_dev);