Fix type mismatch warning in JPEG code (#3664)
Fix type mismatch warning in JPEG code (#3664)

Fixes #3663
lgritz/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio,OpenImageIO/oiio,lgritz/oiio