V4L/DVB (13292): tvp514x: recognize the error case in tvp514x_read_reg()

i2c_smbus_read_byte_data() returns a negative value on error. It is very
likely to be != -1 (-EPERM).

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/tvp514x.c

@@ -272,7 +272,7 @@ static int tvp514x_read_reg(struct v4l2_subdev *sd, u8 reg)
 read_again:
 
 	err = i2c_smbus_read_byte_data(client, reg);
-	if (err == -1) {
+	if (err < 0) {
 		if (retry <= I2C_RETRY_COUNT) {
 			v4l2_warn(sd, "Read: retry ... %d\n", retry);
 			retry++;