Touchpad KCM: Fix synaptics driver issues

Fixes couple of issues:
1.  Remove spurious members of SynapticsTouchpad class from parent class XlibTouchpad; fixing wrong scroll delta values.
2.  Enlarge vertical,horizontal&circular scroll delta and maxtapmove allowing value more than 100. The max value supported by driver is 1000

REVIEW: 127306
BUG: 359460