Input: cyttsp - stop including gpio.h

The driver does not use legacy GPIO API, stop including this header.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/ZrAaOu_vf-cVBhRn@google.com


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