saa7134: Unchecked i2c_transfer function result fixed

Return value of function 'i2c_transfer' is not checked that
may cause undefined behaviour.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 2cf36ac4 ("[PATCH] v4l: 656: added support for the following cards")
Signed-off-by: Aleksandr Burakov <a.burakov@rosalinux.ru>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/pci/saa7134/saa7134-dvb.c

@@ -466,7 +466,9 @@ static int philips_europa_tuner_sleep(struct dvb_frontend *fe)
 	/* switch the board to analog mode */
 	if (fe->ops.i2c_gate_ctrl)
 		fe->ops.i2c_gate_ctrl(fe, 1);
-	i2c_transfer(&dev->i2c_adap, &analog_msg, 1);
+	if (i2c_transfer(&dev->i2c_adap, &analog_msg, 1) != 1)
+		return -EIO;
+
 	return 0;
 }
 
@@ -1018,7 +1020,9 @@ static int md8800_set_voltage2(struct dvb_frontend *fe,
 	else
 		wbuf[1] = rbuf & 0xef;
 	msg[0].len = 2;
-	i2c_transfer(&dev->i2c_adap, msg, 1);
+	if (i2c_transfer(&dev->i2c_adap, msg, 1) != 1)
+		return -EIO;
+
 	return 0;
 }