iio: imu: st_lsm6dsx: get device name from st_lsm6dsx_sensor_settings

Introduce sensor name in st_lsm6dsx_sensor_settings table. This is
a preliminary patch to add I3C support to st_lsm6dsx since i3c_device_id
data structure does not contain a name field

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