Ensure we can read out link status from the CTP6 FE at 904
Created by: ekfriis
This is the analog of @nwoods 's task in #4 (closed), but should be done by @dabelknap at Previssin 904.
Austin, please give it a shot! We need to figure out exactly what bitfiles we need to load onto the FPGAs - see my out-of-band mail to Tom & Mathias.