Input: edt-ft5x06 - mark as direct input device

edt-ft5x06 is a touchscreen and thus a direct input device; let's amrk it
as such. This also allows us to drop some initialization code as
input_init_mt_slots() will do that for us.

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