iio: magnetometer: ak8975: Fix 'Unexpected device' error

iio: magnetometer: ak8975: Fix 'Unexpected device' error

Explicity specify array indices to fix mapping between
asahi_compass_chipset and ak_def_array.
While at it, remove unneeded AKXXXX.

Fixes: 4f9ea93afde1 ("iio: magnetometer: ak8975: Convert enum->pointer for data in the match tables")
Signed-off-by: André Apitzsch <git@apitzsch.eu>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231001-ak_magnetometer-v1-1-09bf3b8798a3@apitzsch.eu
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>