Really, really fix mmx img_4o4mmx routine.
Really, really fix mmx img_4o4mmx routine.

darcs-hash:20080322131529-9beca-4210ca3d9d5218a28604f1ef273d2346f4f40967.gz

nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf