Initial import of psmouse driver from Ubuntu tree

This is import of psmouse driver from Trusty kernel tree
Input: synaptics - quick hack for PressPads

PressPads are found on HP EliteBook 1040 laptops. They lack any kind of
physical buttons, instead they generate primary button click when uses
presses somewhat hard on the surface of the touchpad. Unfortunately they
also report primary button click whenever there are 2 or more contacts
on the pad, messing up all multi-finger gestures (2-finger scrolling,
multi-finger tapping, etc). To cope with this behavior we introduce a
delay in reporting primary press in case more contacts appear.

This is a hack as we do not detect [yet] whenther the device is a
PowerPad or a regular ClickPad.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>