mac80211: support control port TX status reporting

Add support for TX status reporting for the control port
TX API; this will be used by hostapd when it moves to the
control port TX API.

Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
Link: https://lore.kernel.org/r/20200527160334.19224-1-markus.theil@tu-ilmenau.de


[fix commit message, it was referring to nl80211]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>