qtnfmac: add DFS offload support

DFS offload support implemented:
- DFS_OFFLOAD feature is advertised depending on HW capabilities
- CAC_STARTED event forwarding from HW implemented
- start_radar_detection() callback now returning -ENOTSUPP
  if DFS_OFFLOAD is enabled

Signed-off-by: Dmitry Lebed <dlebed@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/quantenna/qtnfmac/event.c

@@ -443,6 +443,17 @@ static int qtnf_event_handle_radar(struct qtnf_vif *vif,
 		cfg80211_cac_event(vif->netdev, &chandef,
 				   NL80211_RADAR_CAC_ABORTED, GFP_KERNEL);
 		break;
+	case QLINK_RADAR_CAC_STARTED:
+		if (vif->wdev.cac_started)
+			break;
+
+		if (!wiphy_ext_feature_isset(wiphy,
+					     NL80211_EXT_FEATURE_DFS_OFFLOAD))
+			break;
+
+		cfg80211_cac_event(vif->netdev, &chandef,
+				   NL80211_RADAR_CAC_STARTED, GFP_KERNEL);
+		break;
 	default:
 		pr_warn("%s: unhandled radar event %u\n",
 			vif->netdev->name, ev->event);