HID: wacom: reuse wacom_parse_and_register() in wireless_work

Removes duplicated code.
The only difference is that we now need to stop and start the attached hid
device, but this is a small cost.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>