kern/57934: Restore FDDI support in the network stack

[thorpej%me.com@localhost]

>Number:         57934
>Category:       kern
>Synopsis:       Restore FDDI support in the network stack
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Wed Feb 14 04:25:00 +0000 2024
>Originator:     Jason Thorpe
>Release:        NetBSD-10.X
>Organization:
Fans of Dietary Fiber Distributed Data Interfaces
>Environment:
(sorry, I can't be bothered)
>Description:
Someone has stepped forward to maintain the FDDI support in the network stack and has requested it be restored.  This problem report tracks that request.  The relevant commit that removed it: https://mail-index.netbsd.org/source-changes/2020/01/20/msg113058.html
>How-To-Repeat:
N/A
>Fix:
Some combination of revert + tweak.