iio: accel: bma180: use iio helper function to guarantee direct mode

Replace the code that guarantees the device stays in direct mode
with iio_device_claim_direct_mode() which does same.
Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/bma180.c

@@ -469,13 +469,14 @@ static int bma180_read_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
 		mutex_lock(&data->mutex);
-		if (iio_buffer_enabled(indio_dev)) {
-			mutex_unlock(&data->mutex);
-			return -EBUSY;
-		}
 		ret = bma180_get_data_reg(data, chan->scan_index);
 		mutex_unlock(&data->mutex);
+		iio_device_release_direct_mode(indio_dev);
 		if (ret < 0)
 			return ret;
 		*val = sign_extend32(ret >> chan->scan_type.shift,