thermal: intel: int340x: Add production mode attribute

It is possible that the system manufacturer locks down thermal tuning
beyond what is usually done on the given platform. In that case user
space calibration tools should not try to adjust the thermal
configuration of the system.

To allow user space to check if that is the case, add a new sysfs
attribute "production_mode" that will be present when the ACPI DCFG
method is present under the INT3400 device object in the ACPI Namespace.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>