Input: elantech - add support for newer (August 2013) devices

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: NDmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/elantech.c

@@ -1313,6 +1313,7 @@ static int elantech_set_properties(struct elantech_data *etd)
 			break;
 		case 6:
 		case 7:
+		case 8:
 			etd->hw_version = 4;
 			break;
 		default: