[media] cx231xx: prepare for i2c_client attachment

This is needed to support PCTV QuatroStick 522e which uses a si2157.
The si2157 driver is written using i2c_client attachment.
Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Tested-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

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

@@ -67,6 +67,7 @@ struct cx231xx_dvb {
 	struct dmx_frontend fe_hw;
 	struct dmx_frontend fe_mem;
 	struct dvb_net net;
+	struct i2c_client *i2c_client_tuner;
 };
 
 static struct s5h1432_config dvico_s5h1432_config = {
@@ -549,11 +550,18 @@ static int register_dvb(struct cx231xx_dvb *dvb,
 
 static void unregister_dvb(struct cx231xx_dvb *dvb)
 {
+	struct i2c_client *client;
 	dvb_net_release(&dvb->net);
 	dvb->demux.dmx.remove_frontend(&dvb->demux.dmx, &dvb->fe_mem);
 	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 */
+	if (client) {
+		module_put(client->dev.driver->owner);
+		i2c_unregister_device(client);
+	}
 	dvb_unregister_frontend(dvb->frontend);
 	dvb_frontend_detach(dvb->frontend);
 	dvb_unregister_adapter(&dvb->adapter);