HID: uclogic: Switch to reporting abstract button events

Based on a patch from: Nikolai Kondrashov <Nikolai.Kondrashov@redhat.com>

Enable abstract keyboard mode for Huion tablets, which makes them report
frame buttons using the pen interface and report ID. Divert these
reports to a virtual report ID describing them.

This makes the tablet compatible with xf86-input-wacom and libinput,
but stops the frame buttons from reporting keyboard events.

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>