Revert "Staging: iio: adt7316: Add an extra check for 'ret' equals to 0"

This reverts commit 00426e99.

i2c_smbus_read_byte() returns 0 when a byte with the value 0 is read from
the device. This is a valid read so revert the check for 0.
Signed-off-by: Jeremy Fertic <jeremyfertic@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/addac/adt7316-i2c.c

@@ -30,10 +30,6 @@ static int adt7316_i2c_read(void *client, u8 reg, u8 *data)
 	}
 
 	ret = i2c_smbus_read_byte(client);
-
-	if (!ret)
-		return -EIO;
-
 	if (ret < 0) {
 		dev_err(&cl->dev, "I2C read error\n");
 		return ret;