Until now, emulation models were always being registered via probe(),
which causes the emulator to initialize all the channels. To reduce the
overhead, the channels were not connected or registered in the bay
until the first event of that model was received. This delayed connect
was causing issues in muxes where the newly connected model required
refreshing the touched channels. Which in turn was causing unexpected
PRV events.
By determining which models we need to enable, we can remove the delayed
connect mechanism and just enable those models at initialization time,
and connect the channels.
Ensures that the select callback will be called on the propagation
phase, immediately setting the right output. Otherwise the mux won't be
updated until the select channel sets a new value.
