defined or a value in the array is "0" then it is assumed
that the frequency is set by the parent clock or a
fixed rate clock source.
+-lanes-per-direction : number of lanes available per direction - either 1 or 2.
+ Note that it is assume same number of lanes is used both
+ directions at once. If not specified, default is 2 lanes per direction.
Note: If above properties are not defined it can be assumed that the supply
regulators or clocks are always on.