batman-adv: Merge bugfixes from 2017.4

batman-adv: Merge bugfixes from 2017.4

* Fix lock for ogm cnt access in batadv_iv_ogm_calc_tq
* Fix check of retrieved orig_gw in batadv_v_gw_is_eligible
* Always initialize fragment header priority
* Avoid spurious warnings from bat_v neigh_cmp implementation
* fix TT sync flag inconsistencies
* Accept only filled wifi station info
* Use default throughput value on cfg80211 error
* do not add loop detection mac addresses to global tt
* Fix rx packet/bytes stats on local ARP reply
* handle race condition for claims between gateways
* fix memory leak when dropping packet from other gateway
* drop unicast packets from other backbone gw
* prevent duplication of ARP replies when DAT is used
* prevent multiple ARP replies sent by gateways if dat enabled
* Initialize gw sel_class via batadv_algo
* Keep fragments equally sized
* decrease maximum fragment size
* don't add loop detect macs to TT
* Treat NET_XMIT_CN as transmit successfully

Signed-off-by: Sven Eckelmann <sven@narfation.org>