Protect VCP buffer pointer with atomic section.
Protect VCP buffer pointer with atomic section.

* Fix issue #313

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