iwlwifi: mvm: add support to the new FW time event API

The time event firmware API will change, add the support for that.
Use the new API throughout and convert to the old where needed.

Signed-off-by: Eytan Lifshitz <eytan.lifshitz@intel.com>
Reviewed-by: Guy Cohen <guy.cohen@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>