Currently libinput does not work with nitrogen6x and touchscreen,
so disable it until problem is resolved.

Change-Id: I5c569f843fbc958faed9da3bd3879aa66efeb5f5
Task-number: QTEE-1032
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>
Reviewed-by: Teemu Holappa <teemu.holappa@theqtcompany.com>