iwlwifi: mvm: make thermal throttling values configurable per NIC family

The thermal throttling parameters were constant and hardcoded, not allowing
changes for different NIC families.
Change this so that the values are part of the NIC family configuration and
are not constant (so they can be changed dynamically in the future).

Signed-off-by: Chaya Rachel Ivgi <chaya.rachel.ivgi@intel.com>
Reviewed-by: Luciano Coelho <luciano.coelho@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>