scsi_debug: fix REPORT LUNS Well Known LU

The use case to report 'REPORT LUNS WLUN' described
in scsi_debug documentation didn't work because:
scsi_scan_host_selected() checks for:
	 lun < shost->max_lun

To fix this we set:
	max_lun = SCSI_W_LUN_REPORT_LUNS + 1;
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

drivers/scsi/scsi_debug.c

@@ -700,7 +700,7 @@ static void sdebug_max_tgts_luns(void)
 		else
 			hpnt->max_id = scsi_debug_num_tgts;
 		/* scsi_debug_max_luns; */
-		hpnt->max_lun = SCSI_W_LUN_REPORT_LUNS;
+		hpnt->max_lun = SCSI_W_LUN_REPORT_LUNS + 1;
 	}
 	spin_unlock(&sdebug_host_list_lock);
 }
@@ -5340,7 +5340,8 @@ static int sdebug_driver_probe(struct device * dev)
 		hpnt->max_id = scsi_debug_num_tgts + 1;
 	else
 		hpnt->max_id = scsi_debug_num_tgts;
-	hpnt->max_lun = SCSI_W_LUN_REPORT_LUNS;	/* = scsi_debug_max_luns; */
+	/* = scsi_debug_max_luns; */
+	hpnt->max_lun = SCSI_W_LUN_REPORT_LUNS + 1;
 
 	host_prot = 0;