wcn36xx: Add TX ack support

The controller is capable of reporting TX indication which can be used
to report TX ack when IEEE80211_TX_CTL_REQ_TX_STATUS is set.
The support was only partially implemented.

The firmware can be configured for reporting event when a packet is
acked, without specifying which packet though. In order to send a
packet flagged with TX status callback, we need to stop the queue,
submit the packet and wait for the firmware ack event. Then the queue
can be restarted and mac80211 status callback called.

In case the packet is not acked, no ack event will be received,
therefore a timeout mechanism is introduced to restart the queue
and call the status cb in case no event is received after a 100ms.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1595586052-16081-3-git-send-email-loic.poulain@linaro.org