iwlwifi: mvm: don't run automatic checks if CT was caused by debugfs

If we're manually testing the CT kill functionality via debugfs, we
shouldn't schedule the work to recheck the temperature after the
ct_kill_duration period has passed.

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