usb cam can't adjust resolution

For the same USB camera, the following code is helpful to adjust the resolution. But the `nanocamera` can't. 
```python
capture = cv2.VideoCapture(3)

if capture.isOpened():
    capture.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
    capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
```
