Add DSB after setting USBDBG IRQ.
Add DSB after setting USBDBG IRQ.

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