Support for watchdog on APU2 boards

[IVI053]

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Is your feature request related to a problem? Please describe.

Hardware watchdog on APU2 boards ist Not supported

Describe the solution you like

It would be helpful for others if the watchdog could be supported in mainline.

Describe alternatives you considered

I tested it manually. The needed driver is available in FreeBSD and is named amdsbwd. After loading it manually and starting watchdogd using rc.syshook.d/early everything works fine.

Additional context

none