iio: imu: st_lsm6dsx: add support to LSM6DSOX

Add support to STM LSM6DSOX 6-axis (acc + gyro) Mems sensor
https://www.st.com/resource/en/datasheet/lsm6dsox.pdf



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