Fix ppm_write to save RGB888
Fix ppm_write to save RGB888

tianzhihen/openmv,iabdalkader/openmv,openmv/openmv,SmartArduino/openmv,iabdalkader/openmv,iabdalkader/openmv,kwagyeman/openmv,kwagyeman/openmv,openmv/openmv,kwagyeman/openmv,tianzhihen/openmv,openmv/openmv,openmv/openmv,SmartArduino/openmv,tianzhihen/openmv,SmartArduino/openmv,iabdalkader/openmv,SmartArduino/openmv,tianzhihen/openmv,kwagyeman/openmv