Input: atkbd - properly handle special keys on Dell Latitudes

Most of Fn+F? special keys on (at least) the Dell Latitude laptops don't
generate a hardware key release event so the driver has to generate one.

Signed-off-by: Giel de Nijs <giel@caffeinetrip.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>