scsi_debug: vpd and mode page work

Cleanup some mode and vpd pages. Stop reporting SBC (disk) pages when
peripheral type is something else (e.g. tape). Update version
descriptors. Expand LBPRZ flag handling.
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>