MFC: r367349, r367854, r368365, r368374(by cem)

MFC: r367349, r367854, r368365, r368374(by cem)

r367349:

atkbdc(4): Add quirk for "System76 lemur Pro" laptops.

Currently atkbdc(4) assumes all coreboot BIOSes belonging to Chromebooks
and unconditionally sets a number of quirks to workaround known issues.

Exclude "System76" laptops from this set as they appeared to be a
traditional hardware ("lemur Pro" is a rebranded Clevo chassis) with
coreboot firmware on board. KBDC_QUIRK_KEEP_ACTIVATED quirk activated for
Chromebook platform makes keyboard on this devices inoperable.

"Purism Librem" laptops may require the same exclusion too.

PR:		250711
Reported by:	nick.lott@gmail.com

r367854:

psm(4): Disable AUX multiplexer probing on all Lenovo laptops.

Rudimentary AUX multiplexing support was added to kernel to make possible
touchpad initialization on some HP EliteBook laptops with trackpoint.

Disable multiplexer probing on all Lenovo laptops now as they use touchpad
pass-through port rather than AUX multiplexer to connect trackpoint and
at least two model (X120e and X121e) is known for getting PS/2 AUX port
dysfunctional after switching back to hidden multiplexing mode.

AUX MUX probing can be reenabled with setting of hw.psm.mux_disabled loader
tunable to 0.

PR:		249987
Reported by:	jwb

r368365:

atkbd(4): Change quirk table end-of-list marker to NULL vendor/maker/product

This fixes regression introduced in r367349 which effectively resulted in
truncation of quirk table.

PR:		250711
Submitted by:	grembo
Reported by:	Matthias Apitz <guru@unixarea.de>

r368374 (by cem):

atkbd(4): Just use nitems() for quirk enumeration

Reviewed by:    imp, wulf
Differential Revision:  https://reviews.freebsd.org/D27489