[ ] combine arbiter/dispatcher
[ ] tag request TLPs to the bus
[ ] use those tags to dispatch TLP responses to the appropriate internal clients

Expose the clocks and resets from the wrapper module so that they can be connected to pins or to the zynq clocks.

Provide a way to specify which pin they are connected to.

This is really only needed for the PCIe case, but let's keep them consistent.

1. Move the control interface to offset 0
2. Add a register for the number of FIFOs and the number of addresses per FIFO
3. Add a register containing the offset of the first FIFO of the interface
4. Add a register containing the offset of the next interface

We will still have the address of a small number of registers hardcoded into the software, but we should not have to hardcode the other offsets into the drivers.

[x] some addresses of the device do not respond to reads, causing CPU lockup
[x] interrupts do not work

In order to eliminate some horrible hacks, let's specify the hardware's request and indication interfaces on the command line.

Also, specify the top module of the hardware on the command line. The top module shall implement an interface that includes the specified request interfaces and shall take interface parameters for each of the indication interfaces.