iflib/bridge kernel panic

>From latest HEAD on a Dell Precision 7550 laptop:

https://gist.github.com/lattera/a0803f31f58bcf8ead51ac1ebbc447e2

The last working boot environment was 14 Aug 2020. If I get some time to
bisect commits, I'll try to figure out the culprit.

Thanks,

Shawn Webb

(Sorry for the brevity. Only partially working system due to above
breakage.)