aoedev_by_aoeaddr
struct aoedev *aoedev_by_aoeaddr(ulong maj, int min, int do_alloc);
d = aoedev_by_aoeaddr(major, minor, 0);
d = aoedev_by_aoeaddr(aoemajor, h->minor, 0);
d = aoedev_by_aoeaddr(aoemajor, h->minor, 1);