ath10k: prevent some tx flushing failures

ath10k: prevent some tx flushing failures

Firmware could request inspection of some
submitted tx requests. Since the callback wasn't
implemented it was possible to bleed tx msdu_ids
which could translate to tx flushing timeouts.

There's nothing ath10k can do to help firmware
with tx processing now so just report all tx
frames as already inspected to prevent firmware
from sending up inspection events and force it to
report regular tx completion indications with
discard status.

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