iio:accel:stk8312: Remove acpi_device_id table

With CONFIG_ACPI=n, W=1 and -Werror, 0-day reports:

drivers/iio/accel/stk8312.c:644:36: error:
	'stk8312_acpi_id' defined but not used

Apparently STK8312 is not a valid ACPI ID. Remove the ID table
as this is the only entry.  If ACPI support is desired an explicit
of_device_id table should be added (rather than relying on the fallback
to the existing ID table).

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>