added comments about vmap for dmabuf items
added comments about vmap for dmabuf items

cambridgehackers/connectal,csail-csg/connectal,cambridgehackers/connectal,hanw/connectal,cambridgehackers/connectal,chenm001/connectal,csail-csg/connectal,hanw/connectal,chenm001/connectal,cambridgehackers/connectal,hanw/connectal,hanw/connectal,8l/connectal,chenm001/connectal,8l/connectal,8l/connectal,chenm001/connectal,8l/connectal,cambridgehackers/connectal,csail-csg/connectal,csail-csg/connectal,chenm001/connectal,csail-csg/connectal,hanw/connectal,8l/connectal