wifi: mt76: mt7996: fix implicit beamforming support for mt7992

wifi: mt76: mt7996: fix implicit beamforming support for mt7992

Fix the ibf_timeout field for mt7996, mt7992 and mt7990 chipsets. For
the mt7992, this value shall be set as 0xff, while the others shall be
set as 0x18.

Fixes: ad4c9a8a9803 ("wifi: mt76: mt7996: add implicit beamforming support for mt7992")
Signed-off-by: Howard Hsu <howard-yh.hsu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Link: https://patch.msgid.link/20251106064203.1000505-3-shayne.chen@mediatek.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>