Add configurable address-width on DMA descriptors.
Add address_width parameters to layout/Endpoint/Crossbar to allow passing the 64-bit addresses from frontend ports (ex DMAs).
Add 64-bit (4DWs Header) support to Packetizer.
Adapt simulation and test for 32-bit/64-bit addressing.
Limitations:
4DWs Packetizer only implemented for 64-bit data-width for now.
When 64-bit addressing support is enabled, requests are always generated in 64-bit format (4DWs). Dynamic switch from 3DWs to 4DWs could be implemented when the 32-MSBs are zeros.
64-bit addressing support not implemented for Root -> Device path.
Limitations: