Optimize Grayscale JPEG.
Optimize Grayscale JPEG.

* Skip UV tables for Grayscale images.

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