Hi, trying to get the colorlight target running with rev 6.1, but it doesn't compile (?), with
```
targets$ ./colorlight_5a_75b.py --revision 6.1  --uart-name=crossover
[..]
 File "[..]/litedram/litedram/common.py", line 84, in __getattr__
    return getattr(self.groups[self.sel], name)
AttributeError: 'Record' object has no attribute 'ba'
```