opencv: disable ffmpeg dependency
opencv: disable ffmpeg dependency

lhmouse/MINGW-packages,oscarfv/MINGW-packages,stahta01/MINGW-packages,stahta01/MINGW-packages,JPeterMugaas/MINGW-packages,oscarfv/MINGW-packages,stahta01/MINGW-packages,lhmouse/MINGW-packages,oscarfv/MINGW-packages,lhmouse/MINGW-packages,stahta01/MINGW-packages,lhmouse/MINGW-packages,oscarfv/MINGW-packages,JPeterMugaas/MINGW-packages,oscarfv/MINGW-packages,stahta01/MINGW-packages,JPeterMugaas/MINGW-packages,stahta01/MINGW-packages,oscarfv/MINGW-packages,lhmouse/MINGW-packages,JPeterMugaas/MINGW-packages,JPeterMugaas/MINGW-packages,lhmouse/MINGW-packages,JPeterMugaas/MINGW-packages