wifi: cfg80211: add a function for reporting TX status with hardware timestamps

Add a function for reporting TX status with hardware timestamps. This
function shall be used for reporting the TX status of Timing
measurement and Fine timing measurement action frames by devices that
support reporting hardware timestamps.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>