ath10k: strip qos data bit always

NativeWifi tx mode expects QoS Data frames to be
delivered as Data frames with QoS part (e.g. tid)
being delievered out-of-band in fw tx command.

The QoS bit wasn't stripped before submitting to
firmware.

Stripping fixes two known problems:

 * qca6174 IOT with some APs, e.g.
   Cisco AIR-AP 1252 (which would crash after
   ath10k association). Some ath9k APs would
   crash as well.

 * sniffing own tx frames via radiotap because,
   e.g. wireshark was seeing QoS bit set but
   since QoS Control was stripped in ath10k it
   would parse beginning of LLC/SNAP

>From debugability point of view this removes the
ability to distinguish QoS from non-QoS frames
when sniffing own tx via radiotap. On the other
hand frames can be now parsed correctly without
special software modification.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>