port-next68k/52204: NeXTstation keyboard is no longer responsive under NetBSD 7.1

[miod%online.fr@localhost]

>Number:         52204
>Category:       port-next68k
>Synopsis:       NeXTstation keyboard is no longer responsive under NetBSD 7.1
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-next68k-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Apr 30 16:30:00 +0000 2017
>Originator:     Miod Vallat
>Release:        7.1
>Organization:
>Environment:
>Description:
Non-turbo NeXTstation slab (68040, 25MHz) with non-ADB keyboard.

Keyboard works in NetBSD 1.6 to 5.0. Booting either 7.0.2 or 7.1, the kernel boots multiuser, network works, but key presses seem to be ignored.
>How-To-Repeat:
Boot NetBSD 7.0.2 or 7.1 on slab.
>Fix: