commit 17c1c9ba upstream.

This reverts commit 36b30d61.

This is necessary to detect paz00 (ac100) touchpad properly as one
speaking ETPS/2 protocol. Without it X.org's synaptics driver doesn't
work as the touchpad is detected as an ImPS/2 mouse instead.

Commit ec6184b1 changed the way
auto-detection is performed on ports marked as pass through and made the
issue apparent.

A pass through port is an additional PS/2 port used to connect a slave
device to a master device that is using PS/2 to communicate with the
host (so slave's PS/2 communication is tunneled over master's PS/2
link). "Synaptics PS/2 TouchPad Interfacing Guide" describes such a
setup (PS/2 PASS-THROUGH OPTION section).

Since paz00's embedded controller is not connected to a PS/2 port
itself, the PS/2 interface it exposes is not a pass-through one.
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Acked-by: Marc Dietrich <marvin24@gmx.de>
Fixes: 36b30d61 ("staging: nvec: ps2: change serio type to passthrough")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>