Input: usbtouchscreen - add new model from IRTOUCHSYSTEMS

This adds support for another model of IRTOUCH SYSTEMS Co.,LtD infrared
touchscreens. The USB vendorID/deviceID is 6615/0012. It is also sold
under the label "Elektrosil".

The datasheet states that coordinates for x and y are in the range from
0 to 32767.

Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>