HID: wacom: generic: Add support for sensor offsets

Many of Wacom's display tablets include an "outbound" area where pen
digitizing is possible but outside of the display area. To accommodate
such sensors in the HID_GENERIC codepath, we add support for the
necessary vendor-defined HID feature usages and adjust the min/max
values of the X and Y axes accordingly, similar to what is done in
the non-generic codepath.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>