Bundle bridge trace interface

* adding dcache om when there is no tim

This reverts commit c69607cf.

Implement debug trigger-sharing and chain-limiting proposals

* removed BundleMonitor
* moved CoreMonitorBundle class to package level

Provide a modicum of TL.A buffering in the NoCrossing case

This prevents livelock in a multi-master system

* adding dcache,icache,rocket, fpu, btb

* refactoring rockettile and adding helper methods to the OM* case classes

* icaches are now optional

* refactored the DCache and ICache OM code

- Don't allow chain to be set if this trigger doesn't belong to D-mode
  but the next trigger does.

- Don't allow dmode to be set if the previous trigger doesn't belong
  to D-mode and has chain set.

- Don't allow chains longer than 2.

Remove a D$ ECC critical path

Added hart array feature

Fix a few issues with multi-chip designs

This actually saves hardware...

These are always on the critical path, and inlining them provides
more opportunity to optimize the control paths in some flows.

Note this doesn't do anything useful without invoking the
firrtl InlineInstances transform.

Tile Notification Nodes