This fixed a problem that showed up in the Fedora development tree a few
weeks before the Fedora Core 4 release, initially as slab corruption, later
as hard crashes on boot up, when slab debugging was disabled for the
release. More details on the history at
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=158424
The problem is caused by sbp2's use of scsi_host->hostdata[0] to hold a
scsi_id, without explicitly requesting space for it. Since hostdata is
declared as a zero-sized array, we don't get any such space by default, so
it must be explicitly requested. The patch below implements just that.