Currently we don't account TX statistics on wlan(4) interfaces. This patch add this accounting.
Since ieee80211_pwrsave() can fail due to queue overflow, check its return code and increment oerrors counter when it fails.
Update obytes and omcasts counters. It seems it is correct to save mbuf's lenght for incrementing obytes before calling ieee80211_encap().
Also update oerrors in case when we don't send mbuf due to some errors.
- Group Reviewers
- rS283313: Properly update TX statistics for wlan(4).
rS283855: MFC r283313: