media: cx231xx: don't check number of messages in the driver

Since commit 1eace834 ("i2c: add param sanity check to
i2c_transfer()"), the I2C core does this check now. We can remove it
from drivers.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/usb/cx231xx/cx231xx-i2c.c

@@ -376,8 +376,6 @@ static int cx231xx_i2c_xfer(struct i2c_adapter *i2c_adap,
 	struct cx231xx *dev = bus->dev;
 	int addr, rc, i, byte;
 
-	if (num <= 0)
-		return 0;
 	mutex_lock(&dev->i2c_lock);
 	for (i = 0; i < num; i++) {