Input: cyttsp - do not force interrupt trigger

Instead of forcing interrupt trigger to be "falling edge" let's rely on the
platform to set it up according to how it is set up on a given board based
on data in device tree or ACPI tables.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/YK7iO96g+7yIC0l1@google.com


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