wifi: mt76: get rid of false alamrs of tx emission issues

When the set_chan_info command is set with CH_SWITCH_NORMAL reason,
even if the action is UNI_CHANNEL_RX_PATH, it'll still generate some
unexpected tones, which might confuse DFS CAC tests that there are some
tone leakages. To get rid of these kinds of false alarms, always bypass
DPD calibration when IEEE80211_CONF_IDLE is set.

Reviewed-by: Evelyn Tsai <evelyn.tsai@mediatek.com>
Signed-off-by: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>