scsi: link in the debug driver last

If the debug driver is built-in, link it in last, so that any real
drivers will probe first, rather than having the debug driver pick the
first scsi slots..

Signed-off-by: Douglas Gilbert <dougg@torque.net>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>