Input: cyapa - do not try to enable proximity reporting on older devices

Avoid the driver generate warning message when the cyapa driver working
with the old Gen5 trackpad device which does not support the proximity
function.  Those old Gen5 trackpad device all have the platform version
less than 2.

Signed-off-by: Dudley Du <dudl@cypress.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>