Input: evdev - switch matching to EV_SYN

Each input device has EV_SYN capability. This is enforced by the input
core which sets this capability bit unconditionally in
input_register_device().

Switch evdev matching from declaring non-zero id->driver_info to match
on EV_SYN so that special handling can be removed from
input_match_device() and "driver_info" field can be removed from
input_device_id structure.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>