cciss: add support for multi lun tape devices

This patch adds support for multi-lun devices in a SAS environment. It's
required for the support of media changers.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
Signed-off-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>