Update system.c to support H7.
Update system.c to support H7.

iabdalkader/openmv,kwagyeman/openmv,openmv/openmv,kwagyeman/openmv,openmv/openmv,kwagyeman/openmv,openmv/openmv,iabdalkader/openmv,iabdalkader/openmv,iabdalkader/openmv,kwagyeman/openmv,openmv/openmv