commit 271329b3 upstream.

Adjust Elantech signature validation to account fo rnewer models of
touchpads.
Reported-and-tested-by: Màrius Monton <marius.monton@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>