99-synaptics-t440s.conf: disable motion tracking in top part of touchpad

This disables motion tracking in the top portion of the touchpad around
the red lines. Instead you can use that part of the touchpad for left/
middle/right clicks only. Very useful.

Example taken from https://bbs.archlinux.org/viewtopic.php?id=172526

Also increased the hysteresis settings a bit for more stability.

Signed-off-by: Scott Garman <sgarman@zenlinux.com>