Input: elantech - fix detection of touchpads where the revision matches a known rate

Make the check to skip the rate check more lax, so that it applies
to all hw_version 4 models.

This fixes the touchpad not being detected properly on Asus PU551LA
laptops.

Cc: stable@vger.kernel.org
Reported-and-tested-by: David Zafra Gómez <dezeta@klo.es>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>