Fix get_histogram with color thresholding.
Fix get_histogram with color thresholding.

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