Fix syntax error with R3DSDK_INCLUDE_DIR (#2509)
Fix syntax error with R3DSDK_INCLUDE_DIR (#2509)

Changed R3DSDKK_INCLUDE_DIR to R3DSDK_INCLUDE_DIR to fix library find errors.
lgritz/oiio,lgritz/oiio,OpenImageIO/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio,OpenImageIO/oiio,lgritz/oiio