zeusminer: Identify the Chip # both in the UI and RPC API

![ZeusMiner Stats](http://www.nwoolls.com/othercontent/BFGMiner%20ZeusMiner%20Per-Core-Chips-IDd.png)
devdetails definitely calls this. That's why I added the check. Without the check devdetails adds a chip=0 to the end.