Fix GEM EvB when the number of OptoHybrids is the maximum supported
This MR fixes a critical issue in the GEM EvB preventing data-taking with the full GE2/1 station at P5.
More specifically, this MR fixes a bug in the EvB itself which was stuck when both following conditions were met:
- The build was configured with the maximum number of OptoHybrids (i.e. 16).
- The first OptoHybrid was enabled.
Additional details are available in the commit message. Tested on both GE1/1 and GE2/1 in the P5 system.
Edited by Laurent Petre