Chiptool chokes on registers with duplicate names and `dimIindex`

See also #89 and #13 for further discussion. In this case the offending XML is:

```xml

2
0x4
MBIU,RAM0
BUSSCNT%s
Slave Bus Control Register %s
0x1108
```

```xml

4
0x4
P0B,P2B,P3B,P4B
BUSSCNT%s
Slave Bus Control Register %s
0x1114
```

And chiptool panics with a failed assertion for unique names.