In general using ACPI_PTR() leads to more fragile code for a very
minor saving in storage in the case of !CONFIG_ACPI so in IIO we
prefer not to use it if the only ACPI specific code is the acpi_device_id
table.

In this case will also suppress a unused variable warning.
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202302142222.vVU0E4eu-lkp@intel.com/
Cc: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20231231183514.566609-2-jic23@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>