kern/60055: bridge doesn't work well with urtwn(4)

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>Number:         60055
>Category:       kern
>Synopsis:       bridge doesn't work well with urtwn(4)
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Mar 04 12:05:00 +0000 2026
>Originator:     YAMAMOTO Takashi
>Release:        NetBSD current
>Organization:
>Environment:
amd64
>Description:
for some reasons, adding urtwn0 as a physical port of a bridge(4) didn't work.
other members of the bridge: vether0, tap (for qemu/nvmm)
namely a host on the urtwn0's segment <-> tap/vether couldn't communicate.

* almost same configuration using wm0 instead of urtwn0 worked well.
* urtwn0 itself works well if i use it without bridge.

>How-To-Repeat:

>Fix: