A lot of utility code was just being imported willy-nilly from one
package to another. This moves the common code into util to make things
more sensible. The code moved were
* The AsyncQueue and AsyncDecoupledCrossing from junctions.
* All of the code in rocket's util.scala
* The BlackBox asynchronous reset registers from uncore.tilelink2
* The implicit definitions from uncore.util
The old value 62 seems to have been a typo introduced over 2 years ago
in commit 63bd0b9d2a. The intent was to
fit the dhrystone working set (rofl) which the new value of 40 does.
