wifi: mt76: mt7996: fix rx rate report for CBW320-2

wifi: mt76: mt7996: fix rx rate report for CBW320-2

[ Upstream commit 0197923ecf5eb4dbd785f5576040d49611f591a4 ]

RX vector reports channel bandwidth 320-1 and 320-2 with different
values. Fix it to correctly report rx rate when using CBW320-2.

Fixes: 80f5a31d2856 ("wifi: mt76: mt7996: add support for EHT rate report")
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>