ACPI: property: Fix type detection of unified integer reading functions

The current code expects the type of the value to be an integer type,
instead the value passed to the macro is a pointer.
Ensure the size comparison uses the correct pointer type to choose the
max value, instead of using the integer type.

Fixes: 92304413 ("ACPI: property: Unify integer value reading functions")
Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>