ath10k: remove per-packet completion handling

Having a tx completion handler in the
ath10k_skb_cb is very costly (memory wise). The
saved space will be used to merge htt_tx_info.

kvalo: fix ununsed variable in ath10k_wmi_htc_tx_complete()

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: remove `priv` from ath10k_skb_cb

Introduce msdu_id into ath10k_skb_cb to keep track
of htt-related metadata.

This frees up 8 bytes of space in ath10k_skb_cb
making it easier to merge htt_tx_info.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: share htt tx completion for data/mgmt tx

Removes code redundancy and eases future
refactoring up.

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