Input: ALPS - rework detection of Pinnacle AGx touchpads

The official ALPS driver uses the EC report, not the E7 report, to detect
these devices.  Also, they check for a range of values; the original
table-based code only checked for two specific ones.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Tested-by: Dave Turvene <dturvene@dahetral.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>