The XP-PEN Deco L (UGEE) needs to be initialized by sending a buffer of
magic data, discovered by sniffing the Windows driver traffic.

In order to differentiate UGEE tablets that need this kind of
initialization from the previous ones, name them v2 internally and
create an entry point for them.

After initialization, the template report descriptors can be discovered
by parsing a string descriptor, similar to the one exposed by HUION v1
devices.

Add all the required elements to support the device.
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>