staging: wfx: fix case where AP stop with CAB traffic pending

When driver has Content After DTIM Beacon (CAB) in queue, it wait for an
indication from the firmware. However, when we stop to send beacons,
this indication may never happen.

Solve this issue by simply simulate this indication. Firmware will send
data that probably nobody will heard.
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200401110405.80282-32-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/sta.c

@@ -686,6 +686,19 @@ static void wfx_join_finalize(struct wfx_vif *wvif,
 	}
 }
 
+void wfx_enable_beacon(struct wfx_vif *wvif, bool enable)
+{
+	// Driver has Content After DTIM Beacon in queue. Driver is waiting for
+	// a signal from the firmware. Since we are going to stop to send
+	// beacons, this signal will never happens. See also
+	// wfx_suspend_resume_mc()
+	if (!enable && wfx_tx_queues_has_cab(wvif)) {
+		wvif->after_dtim_tx_allowed = true;
+		wfx_bh_request_tx(wvif->wdev);
+	}
+	hif_beacon_transmit(wvif, enable);
+}
+
 void wfx_bss_info_changed(struct ieee80211_hw *hw,
 			     struct ieee80211_vif *vif,
 			     struct ieee80211_bss_conf *info,
@@ -724,7 +737,7 @@ void wfx_bss_info_changed(struct ieee80211_hw *hw,
 
 	if (changed & BSS_CHANGED_BEACON_ENABLED &&
 	    wvif->state != WFX_STATE_IBSS)
-		hif_beacon_transmit(wvif, info->enable_beacon);
+		wfx_enable_beacon(wvif, info->enable_beacon);
 
 	if (changed & BSS_CHANGED_BEACON_INFO)
 		hif_set_beacon_wakeup_period(wvif, info->dtim_period,