puc.4: Cleanup

+ Alphabetize and condense supported hardware.
+ Mention PCI/PCIe where applicable.
+ Move hardware support file to FILES
+ Tag spdx

MFC after: 3 days
Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/1692
Closes: https://github.com/freebsd/freebsd-src/pull/1692