iio: imu: st_lsm6dsx: fix naming of 'struct iio_info' in st_lsm6dsx_shub.c.

We need the name 'st_lsm6dsx_ext_info' for the actual 'iio_chan_spec_ext_info'.
Rename the 'st_lsm6dsx_ext_info' in st_lsm6dsx_shub.c to 'st_lsm6dsx_shub_info'.
For consistency, replace also 'ext' by 'shub' in 'st_lsm6dsx_ext_attributes'
and 'st_lsm6dsx_ext_attribute_group'.

Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/1673874434-30750-2-git-send-email-Philippe.DeMuyter@macq.eu


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>