Added detection for newer Elantech touchpads, so that kernel doesn't
fall-back to default PS/2 driver. Supports touchpads released after
~August 2013. Fixes bug:
https://lists.launchpad.net/kernel-packages/msg18481.html
Tested on an Acer Aspire S7-392-6302.
Signed-off by: Matt Walker <matt.g.d.walker@gmail.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>