Input: elantech - relax signature checks

Input: elantech - relax signature checks

commit a083632eaf6231162b33e40561cfec6a9c156945 upstream.

Apparently there are Elantech touchpads that report non-zero in the 2nd byte
of their signature. Adjust the detection routine so that if 2nd byte is
zero and 3rd byte contains value that is not a valid report rate, we still
assume that signature is valid.

Tested-by: Eric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>