iio: accel: adxl345: Extract adxl345_powerup() helper

For the sake of symmetry and possible reuse in the future
extract adxl435_powerup() helper.

Signed-off-by: Andy Shevchenko <[e-mail]>
Tested-by: Kai-Heng Feng <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/accel/adxl345_core.c

···
 	.write_raw_get_fmt	= adxl345_write_raw_get_fmt,
 };
 
+static int adxl345_powerup(void *regmap)
+{
+	return regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_MEASURE);
+}
+
 static void adxl345_powerdown(void *regmap)
 {
 	regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_STANDBY);
···
 	indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
 
 	/* Enable measurement mode */
-	ret = regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
-			   ADXL345_POWER_CTL_MEASURE);
+	ret = adxl345_powerup(data->regmap);
 	if (ret < 0)
 		return dev_err_probe(dev, ret, "Failed to enable measurement mode\n");