Now most pertinent RBV records are not processed when acquisition is
ongoing.
A few records like LinkStatus and IsAcquiring are still scanned for
obvious reasons, but if we find out that this could not be the case, we
change it.

I still think this should also be treated in the API layer.

ADCVal and AnalogMon should process in the correct order for us to know
what we are reading.

We use PHAS field to make sure everything is processed after we have
checked that IsAcquiring is 0.