HID: uclogic: Rename Huion HS64 PID to Huion Tablet 2

Since the 006d Huion PID is used by multiple tablets (at least HS64 and
HS610), rename its constant to a more general
"USB_DEVICE_ID_HUION_TABLET2".

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
