iio: imu: fxos8700: fix swapped ACCEL and MAGN channels readback

Because ACCEL and MAGN channels data register base address is
swapped the accelerometer and magnetometer channels readback is
swapped.

Fixes: 84e5ddd5 ("iio: imu: Add support for the FXOS8700 IMU")
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Link: https://lore.kernel.org/r/20221208071911.2405922-3-carlos.song@nxp.com


Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>