wifi: mt76: mt792x: add struct mt792x_bss_conf

wifi: mt76: mt792x: add struct mt792x_bss_conf

We are introducing a new structure, mt792x_bss_conf, to manage per-link
configurations in preparation for future STA support of Multi-Link
Operation (MLO).

The patch does not include any logic changes, only structural changes.

We have moved relevant parameters from the mt7921x_vif structure such
as to mt76 of mt76_vif structure, rssi and Tx queue parameters to
mt7921x_bss_conf structure. We can access those members to configure the
BSS for this interface, whether it is our own BSS or the one we are
associated with.

However, we have not yet created the per-link BSS configuration indexed by
link ID for Multi-Link Device (MLD) support. This step needs to be
extended before adding MLD support for AP mode.

Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Link: https://patch.msgid.link/20240613030241.5771-2-sean.wang@kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>