ath10k: rework tx queue locking

Tx queue locking was very simple until now.
Multi-channel support will require a more flexible
and fine grained control.

This introduces a per-hw and per-vif (each with a
bitmask of reasons) tx queue locking.

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