wlcore: cancel channel switch work on interface removal

Otherwise, if the work is pending, we might get
a bad dereference after the interface is removed.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/ti/wlcore/main.c

@@ -2589,6 +2589,7 @@ unlock:
 	cancel_work_sync(&wlvif->rx_streaming_enable_work);
 	cancel_work_sync(&wlvif->rx_streaming_disable_work);
 	cancel_delayed_work_sync(&wlvif->connection_loss_work);
+	cancel_delayed_work_sync(&wlvif->channel_switch_work);
 
 	mutex_lock(&wl->mutex);
 }