commit 8669cf67 upstream.

On Toshiba Satellite C850D, the touchpad and the keyboard might randomly
not work at boot. Preventing MUX mode activation solves this issue.
Signed-off-by: Anisse Astier <anisse@astier.eu>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>