wifi: mt76: mt7996: set correct wcid in txp

Set correct wcid in txp to let the SDO hw module look into the correct
wtbl, otherwise the tx descriptor may be wrongly fiiled. This patch also
fixed the issue that driver could not correctly report sta statistics,
especially in WDS mode, which misled AQL.

Fixes: 98686cd2 ("wifi: mt76: mt7996: add driver for MediaTek Wi-Fi 7 (802.11be) devices")
Co-developed-by: Michael-CY Lee <michael-cy.lee@mediatek.com>
Signed-off-by: Michael-CY Lee <michael-cy.lee@mediatek.com>
Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>