Fix input of tiled images with per-channel formats.
Fix input of tiled images with per-channel formats.

micler/oiio,OpenImageIO/oiio,cwilling/oiio,lgritz/oiio,scott-wilson/oiio,cwilling/oiio,lgritz/oiio,cwilling/oiio,OpenImageIO/oiio,micler/oiio,sambler/oiio,OpenImageIO/oiio,sambler/oiio,cwilling/oiio,micler/oiio,YangYangTL/oiio,mcanthony/oiio,lgritz/oiio,micler/oiio,YangYangTL/oiio,mcanthony/oiio,bdeluca/oiio,scott-wilson/oiio,YangYangTL/oiio,bdeluca/oiio,OpenImageIO/oiio,lgritz/oiio,YangYangTL/oiio,mcanthony/oiio,scott-wilson/oiio,sambler/oiio,bdeluca/oiio,bdeluca/oiio,sambler/oiio,mcanthony/oiio,scott-wilson/oiio