batman-adv: import Linux 4.7 fixes

Introduce new fixes:

 * Avoid nullptr dereference in bla after vlan_insert_tag
 * Avoid nullptr dereference in dat after vlan_insert_tag
 * Avoid tt_req_node list put for unhashed entry
 * Fix orig_node_vlan leak on orig_node_release
 * Fix non-atomic bla_claim::backbone_gw access
 * Fix reference leak in batadv_find_router
 * Free last_bonding_candidate on release of orig_node

Also replace the gluon version of the speedyjoin patch with the one already
included in openwrt-routing.

Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>