If frontend is not attached, both cx88-dvb and saa7134-dvb don't
register DVB. However, dvb unregister were inconditionally called.
Due to that, an OOPS is generated.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
        struct cx8802_dev *dev = drv->core->dvbdev;
 
        /* dvb */
-       videobuf_dvb_unregister(&dev->dvb);
+       if (dev->dvb.frontend)
+               videobuf_dvb_unregister(&dev->dvb);
 
        vp3054_i2c_remove(dev);
 
 
                        }
                }
        }
-       videobuf_dvb_unregister(&dev->dvb);
+       if (dev->dvb.frontend)
+               videobuf_dvb_unregister(&dev->dvb);
        return 0;
 }