Fix that gets raw2dng.py working again.

[mcnalu]

Fix that gets raw2dng.py working again by supporting fmt in init of camdefs.py.

[osexpert]

I tried your changes in 4.0.9 but got another error instead:
Before:

    width, height = self.model.fmt.get("size", (0,0))
AttributeError: 'RaspberryPiHqCamera' object has no attribute 'fmt'

After:

    self.fmt['size']=(width,height)
TypeError: list indices must be integers or slices, not str

[mcnalu]

It looks like you've supplied fmt as a list but it should be a dict. Here's an example that works on 4.0.9 for me:

    fmt={}
    fmt['format']='SRGGB12_CSI2P'
    fmt['stride']=3072

    # choose a predefined camera model, set the sensor mode and bayer layout. 
    # this camera model class sets the appropriate DNG's tags needed based on the camera sensor. ( needed for bit unpacking, color matrices )
    #3 is 4056 by 3040, 12bpp
    #2 is 2028 by 1520, 12bpp, no crop so 2x2 bin I think
    camera = RaspberryPiHqCamera(2, fmt, CFAPattern.BGGR)