Add missing cell pin default connections

[clavin-xlnx]

Track the issue chipsalliance/fpga-interchange-tests#40. The goal is to provide cell pin default connections for a new instance.

[mkurc-ant]

Is there a chance for having this information included in device resource in foreseeable future? I don't think that Vivado itself currently provides that information.

[clavin-xlnx]

@mkurc-ant Please take a look at the latest commit (c531144), I've attempted to populate the Interchange Device schema with cell pin static default values per @gatecat technique of extracting from Vivado.

[mkurc-ant]

@clavin-xlnx Thanks, I'll look into data produced with this change.

[mkurc-ant]

@clavin-xlnx I've checked the generated device resources and the required data is there and appears to be correct.

[clavin-xlnx]

Closing for now, please reopen if any issues are found with the data.