Feature: Zynq-7000 support

[dragonmux]

Detailed description

This PR re-introduces support for the Zynq-7000 series parts, but in a more formal way and less experimental. This support wound up dropped during the rewrite of the Cortex-A support due to having to pry the core implementation apart from this support.

This has been tested on a Zynq 7020 on the Arty-Z7.

This PR includes proper handling of reset quirks and support for debug, and the memory map for the RAM on device.

Your checklist for this pull request

• I've read the Code of Conduct
• I've read the guidelines for contributing to this repository
• It builds for hardware native (make PROBE_HOST=native)
• It builds as BMDA (make PROBE_HOST=hosted)
• I've tested it to the best of my ability
• My commit messages provide a useful short description of what the commits do

Closing issues

[esden]

Fantastic!