ath10k: fix bmi exchange tx/rx race

It was possible for tx completion not to be
processed. In that case an old stack pointer was
left on copy engine tx ring. Next bmi exchange
would immediately pop it and use complete() on the
completion struct there causing corruption.

Make sure to wait for both tx and rx completions
properly.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: sanitize tx ring index access properly

The tx ring index was immediately trimmed with a
bitmask. This discarded the 0xFFFFFFFF error case
(which theoretically can happen when a device is
abruptly disconnected) and led to using an invalid
tx ring index. This could lead to memory
corruption.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: handle attention flags correctly when A-MSDU

In case of A-MSDU RX we should check flags for all
MSDU subframes to be sure we have correct FCS status.

Before we check attention flags only for first frame
where we didn't have correct info about FCS status in
case of A-MSDU. Next didn't mark RX_FLAG_FAILED_FCS_CRC
for skb. As a side efect we see big TP drop when TCP used.
This was easy to reproduce when AP interface was used
and added monitor interface run in promiscuous mode.

Reported-by: Denton Gentry <denton.gentry@gmail.com>
Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>