wifi: ath12k: ath12k_mac_op_tx(): MLO support

For a frame transmission for an ML vif, mac80211 mentions transmit link id in
the tx control info. Use it to convert the RA/TA to the corresponding link sta
and link vif address before enqueueing the frame for transmission.

For 802.3 data frames, always enqueue the frame on the primary (assoc) link id.
Firmware does the link selection, builds 802.11 header and therefore the address
translation too.

Also ensure right link vif is used for WMI based management transmission and
add comments to document when RCU read lock is held.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
Co-developed-by: Rameshkumar Sundaram <quic_ramess@quicinc.com>
Signed-off-by: Rameshkumar Sundaram <quic_ramess@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://patch.msgid.link/20241126171139.2350704-3-kvalo@kernel.org