nl80211: use_monitor and non-mac80211 drivers

[Johannes Berg]

On Mon, 2016-10-31 at 14:44 -0500, Joel Cunningham wrote:
> Actually, studying further, it looks like when drv->device_ap_sme is
> set to 1 (which is the case with my full MAC driver) the monitor
> interface is explicitly disabled and we don’t call
> nl80211_mgmt_subscibe_ap().  So it appears that cfg80211 APIs are
> always used for receiving management frames and poll command/TX
> status support doesn’t matter.
> 
> Is my understanding correct?

Yes, more or less. However, the management TX/RX APIs might still get
used for some higher-level purposes, I think.

The monitor interface is something pretty much historic, we should
perhaps consider removing support for it - it hasn't been used for
about 5 years, since kernel 3.3 I believe.

johannes