mac80211: TDLS: fix skb queue/priority assignment

If the TDLS setup happens over a connection to an AP that
doesn't have QoS, we nevertheless assign a non-zero TID
(skb->priority) and queue mapping, which may confuse us or
drivers later.

Fix it by just assigning the special skb->priority and then
using ieee80211_select_queue() just like other data frames
would go through.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>