Thorsten reported on <fa6e3ee2-91b5-a54b-afe3-87f30aac7a48@leemhuis.info> that
commit c9353bf4 made ath10k unstable with QCA6174 on his Dell XPS13 (9360)
with an error message:

ath10k_pci 0000:3a:00.0: failed to extract amsdu: -11

It only seemed to happen with certain APs, not all, but when it happened the
only way to get ath10k working was to switch the wifi off and on with a hotkey.

As this commit made things even worse (a warning vs breaking the whole
connection) let's revert the commit for now and while the issue is being fixed.

Link: http://lists.infradead.org/pipermail/ath10k/2017-October/010227.htmlReported-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>