Summary:
This change will allow correct args to pass from mboard to dboards,
that in turn can be useful for dboard manager.
Details:
In N310, the dboard manager needs the time source to be updated before
calling update_ref_clock_source(), because it will trigger a reinit of
the dboard, for which the time_source is essential to determine correct
clock synchronizer settings.
The special case is the white rabbit time source needs a different
internal ref_clock_frequency for the clock synchronizer than the passed
in ref_clock_freq.