Input: synaptics - split device info into a separate structure

In preparation for SMBus/Intertouch device support, move static device
information that we query form the touchpad upon initialization into
separate structure. This will allow us to query the device without
allocating memory first.

Also stop using "unsigned long", everything fits into 32 bit chunks.

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>