linux-phytec-ti

HID: ntrig: document sysfs interface

Add sysfs documentation for N-Trig touchscreens under Documentation/ABI.
Descriptions have been collected from code comments.

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>