Input: wacom - add product id used by Samsung Slate 7

New product ID reported by Harvey Braun on linuxwacom mailing list
and also tested this patch with new hardware.

Signed-off-by: Chris Bagwell <chris@cnpbagwell.com>
Acked-by: Ping Cheng <pinglinux@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>