The WACOM_HID_WD_TOUCHRINGSTATUS usage is a single bit which tells us
whether the touchring is currently in use or not. Because we need to
reset the axis value to 0 when the finger is removed, we call
'wacom_map_usage' to ensure that the required type/code values are
associated with the usage. The 'wacom_map_usage' also sets up the axis
range and resolution, however, which is not desired in this particular
case.

Although xf86-input-wacom doesn't do really do anything with the ring's
range or resolution, the libinput driver (for Wayland environments)
uses these values to provide proper angle indications to userspace.

Fixes: 60a22186

 ("HID: wacom: generic: add support for touchring")
Cc: stable@vger.kernel.org
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>