wifi: mt76: mt7996: fix queue pause after scan due to wrong channel switch reason

wifi: mt76: mt7996: fix queue pause after scan due to wrong channel switch reason

Previously, we used the IEEE80211_CONF_IDLE flag to avoid setting the
parking channel with the CH_SWITCH_NORMAL reason, which could trigger TX
emission before bootup CAC.

However, we found that this flag can be set after triggering scanning on a
connected station interface, and the reason CH_SWITCH_SCAN_BYPASS_DPD will
be used when switching back to the operating channel, which makes the
firmware failed to resume paused AC queues.

Seems that we should avoid relying on this flag after switching to single
multi-radio architecture. Instead, use the existence of chanctx as the
condition.

Signed-off-by: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Link: https://patch.msgid.link/20260203155532.1098290-4-shayne.chen@mediatek.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>