HID: lenovo: Add support for IBM/Lenovo Scrollpoint mice

The IBM/Lenovo Scrollpoint mice feature a trackpoint-like stick instead of a
scrolling wheel capable of 2-D (vertical+horizontal) scrolling.  hid-generic
does only expose 1-D (vertical) scrolling functionality for these mice.  This
patch adds support for horizontal scrolling for the IBM/Lenovo Scrollpoint mice
to hid-lenovo.

[jkosina@suse.cz: remove change versioning from git changelog]
Signed-off-by: Peter Ganzhorn <peter.ganzhorn@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Peter De Wachter <pdewacht@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>