Staging: iio/adc/ad7150: release lock on error

The error_ret label should have been before the mutex_unlock().  It's
a typo.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/adc/ad7150.c

@@ -332,8 +332,8 @@ static int ad7150_write_event_value(struct iio_dev *indio_dev,
 	/* write back if active */
 	ret = ad7150_write_event_params(indio_dev, event_code);
 
-	mutex_unlock(&chip->state_lock);
 error_ret:
+	mutex_unlock(&chip->state_lock);
 	return ret;
 }