iio: convert to common i2c_check_functionality() return value

Previously most drivers that used a i2c_check_functionality() check
condition required various error codes on failure. This patchset
converts to a standard of -EOPNOTSUPP

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/humidity/htu21.c

@@ -192,7 +192,7 @@ static int htu21_probe(struct i2c_client *client,
 				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
 		dev_err(&client->dev,
 			"Adapter does not support some i2c transaction\n");
-		return -ENODEV;
+		return -EOPNOTSUPP;
 	}
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));