iwlwifi: mvm: Thermal management fixes

Hi Everyone,

There are a few thermal management shortcomings in the iwlwifi driver that are addressed by this series.

First off, the fw_trips_index[] array field in struct iwl_mvm_thermal_device is only populated and never read, and the code populating it has problems, so patch [1/3] removes it.

Second, iwl_mvm_thermal_zone_register() populates the trip table after passing it to thermal_zone_device_register_with_trips() which is too late, because it can get used before it is populated. It also may as well use THERMAL_TEMP_INVALID as the "invalid temperature" value. Both these issues are addressed by patch [2/3].

Finally, iwl_mvm_send_temp_report_ths_cmd() accesses the trip tables used during thermal zone registration directly in order to obtain the current trip point temperature values, which is not guaranteed to work in the future, because the core will store the trips information in its own copy of the trip table - see this patch series:

https://lore.kernel.org/linux-pm/2728491.mvXUDI8C0e@kreacher/

If possible, I'd like to route the $subject series through the thermal tree, it is requisite for the above one.

Thanks!