ath10k: fix per-vif queue locking

Whenever any vdev was supposed to be paused all Tx
queues were stopped (except offchannel) instead of
only these associated with the given vdev.

This caused subtle issues with
multi-channel/multi-vif scenarios, e.g.
authentication of station vif could sometimes fail
depending on fw tx pause request timing.

Fixes: b4aa539d ("ath10k: implement tx pause wmi event")
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>