iio: magnetometer: ak8975: Convert enum->pointer for data in the match tables

Convert enum->pointer for data in the match tables to simplify the probe()
by replacing device_get_match_data() and i2c_client_get_device_id by
i2c_get_match_data() as we have similar I2C, ACPI and DT matching table.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230818075600.24277-2-biju.das.jz@bp.renesas.com


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