drivers/sensor: lsm6dso: Remove LE to CPU conversions

In ST HAL v2.00, the functions to get the raw sensors values, e.g.
lsm6dso_acceleration_raw_get(), convert from little-endian to CPU.

Previous versions of ST HAL didn't do this.

The conversion here in the driver is converting a second time.  It's not
an issue on a LE system, the conversion is a no-op, but on a BE system
it would be broken.

Signed-off-by: Trent Piepho <trent.piepho@igorinstitute.com>