scsi_debug: vfree is null safe so drop the check

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

@@ -4955,9 +4955,7 @@ bus_unreg:
 dev_unreg:
 	root_device_unregister(pseudo_primary);
 free_vm:
-	if (map_storep)
 	vfree(map_storep);
-	if (dif_storep)
 	vfree(dif_storep);
 	vfree(fake_storep);
 
@@ -4976,9 +4974,7 @@ static void __exit scsi_debug_exit(void)
 	bus_unregister(&pseudo_lld_bus);
 	root_device_unregister(pseudo_primary);
 
-	if (dif_storep)
 	vfree(dif_storep);
-
 	vfree(fake_storep);
 }