Retain min/max when copying inherited latency from
connected ports.
When there is a direct connection port A out -> port B in,
min/max latency range should be retained in direction
of signal flow.
Ardour can only adjust latency in reverse direction of signal flow
to match min = max with an internal delay-line. ie set playback
latency of an input port, or capture latency of an output port.
4998b2711b