mod/system_coordinator: Add initial module
This patch adds the system coordinator module to the power management framework. The system coordinator is responsible for managing each phase of power management.
Each phase is an API call to a module. The phase API and time are configurable elements. Coordinator calls the next phase after the phase timer alarm elapses. The order of the phases follows the element order.
A cycle timer alarm periodically notifies the coordinator to call all the phases again. The cycle time is configurable and must be more than the sum of all phase time.
Signed-off-by: Wen Ping Teh wenping.teh@arm.com