[media] cx231xx: Prepare for attaching new style i2c_client DVB demod drivers

cx231xx does not yet support attaching new-style i2c_client DVB demod
drivers. Add necessary code base on tuner support for i2c_client.
Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/cx231xx/cx231xx-dvb.c

@@ -65,6 +65,7 @@ struct cx231xx_dvb {
 	struct dmx_frontend fe_hw;
 	struct dmx_frontend fe_mem;
 	struct dvb_net net;
+	struct i2c_client *i2c_client_demod;
 	struct i2c_client *i2c_client_tuner;
 };
 
@@ -586,8 +587,14 @@ static void unregister_dvb(struct cx231xx_dvb *dvb)
 	dvb->demux.dmx.remove_frontend(&dvb->demux.dmx, &dvb->fe_hw);
 	dvb_dmxdev_release(&dvb->dmxdev);
 	dvb_dmx_release(&dvb->demux);
-	client = dvb->i2c_client_tuner;
 	/* remove I2C tuner */
+	client = dvb->i2c_client_tuner;
+	if (client) {
+		module_put(client->dev.driver->owner);
+		i2c_unregister_device(client);
+	}
+	/* remove I2C demod */
+	client = dvb->i2c_client_demod;
 	if (client) {
 		module_put(client->dev.driver->owner);
 		i2c_unregister_device(client);