VR9 boxes, 6.20 firmware:
 * use 3490 6.20 kernel sources for all VR9 boxes ('''EXPERIMENTAL''')
 * compile-tested only
 * refs #2418


git-svn-id: file:///var/svn/freetz/trunk@12486 149334a1-2f27-0410-a3b9-fc62619ac1e6