mt76: mt7915: enable radar background detection

Notify userland the hw supports background radar/CAC detection.
Tested-by: NOwen Peng <owen.peng@mediatek.com>
Signed-off-by: NLorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: NFelix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7915/init.c

@@ -309,6 +309,7 @@ static void
 mt7915_init_wiphy(struct ieee80211_hw *hw)
 {
 	struct mt7915_phy *phy = mt7915_hw_phy(hw);
+	struct mt76_dev *mdev = &phy->dev->mt76;
 	struct wiphy *wiphy = hw->wiphy;
 	struct mt7915_dev *dev = phy->dev;
 
@@ -337,6 +338,12 @@ mt7915_init_wiphy(struct ieee80211_hw *hw)
 	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_BEACON_RATE_VHT);
 	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_BEACON_RATE_HE);
 
+	if (!mdev->dev->of_node ||
+	    !of_property_read_bool(mdev->dev->of_node,
+				   "mediatek,disable-radar-background"))
+		wiphy_ext_feature_set(wiphy,
+				      NL80211_EXT_FEATURE_RADAR_BACKGROUND);
+
 	ieee80211_hw_set(hw, HAS_RATE_CONTROL);
 	ieee80211_hw_set(hw, SUPPORTS_TX_ENCAP_OFFLOAD);
 	ieee80211_hw_set(hw, SUPPORTS_RX_DECAP_OFFLOAD);