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

drivers/input/touchscreen/cyttsp_core.c

@@ -17,7 +17,6 @@
 #include <linux/input.h>
 #include <linux/input/mt.h>
 #include <linux/input/touchscreen.h>
-#include <linux/gpio.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/property.h>