scsi: scsi_debug: Fix memory leak if LBP enabled and module is unloaded

BugLink: http://bugs.launchpad.net/bugs/1642572

commit 4d2b496f upstream.

map_storep was not being vfree()'d in the module_exit call.
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/scsi/scsi_debug.c

@@ -4981,6 +4981,7 @@ static void __exit scsi_debug_exit(void)
 	bus_unregister(&pseudo_lld_bus);
 	root_device_unregister(pseudo_primary);
 
+	vfree(map_storep);
 	vfree(dif_storep);
 	vfree(fake_storep);
 }