iio: imu: st_lsm6dsx: fix checkpatch warning

Fix following checkpatch warning:

CHECK: Alignment should match open parenthesis
+static int st_lsm6dsx_read_event(struct iio_dev *iio_dev,
+                                  const struct iio_chan_spec *chan,

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>