Extend mt7925_mcu_set_tx with per-link BSS configuration.

The patch we created is a prerequisite to enable the MLO function in the
driver. It is purely a refactoring patch so the functionality should
remain unchanged.
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/20240613030241.5771-7-sean.wang@kernel.orgSigned-off-by: Felix Fietkau <nbd@nbd.name>