staging: ste_rmi4: remove gpio.h include

gpio.h is not needed and is going to be removed.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>

drivers/staging/ste_rmi4/board-mop500-u8500uib-rmi4.c

@@ -5,7 +5,6 @@
 #include <linux/i2c.h>
 #include <linux/gpio.h>
 #include <linux/interrupt.h>
-#include <mach/gpio.h>
 #include <mach/irqs.h>
 #include "synaptics_i2c_rmi4.h"