wifi: ath10k: Serialize wake_tx_queue ops

Serialize the ath10k implementation of the wake_tx_queue ops.
ath10k_mac_op_wake_tx_queue() must not run concurrent since it's using
ieee80211_txq_schedule_start().

The intend of this patch is to sort out an issue discovered in the discussion
referred to by the Link tag.

I can't test it with real hardware and thus just implemented the per-ac queue
lock Felix suggested. One obvious alternative to the per-ac lock would be to
bring back the txqs_lock commit bb2edb73 ("ath10k: migrate to mac80211 txq
scheduling") dropped.

Fixes: bb2edb73 ("ath10k: migrate to mac80211 txq scheduling")
Reported-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/519b5bb9-8899-ae7c-4eff-f3116cdfdb56@nbd.name


CC: <stable@vger.kernel.org>
Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230323165527.156414-1-alexander@wetzel-home.de