Input: edt-ft5x06 - remove EV_SYN event report

input_register_device already sets the EV_SYN event since all devices can
generate them.

Remove the redundant affectation.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>