[ARM] S3C24XX: Fix sparse error in gpiolib.c

Fix the following sparse error generated by including
<plat/gpio-core.h> instead of <mach/gpio-core.h>

gpiolib.c:78:22: warning: symbol 's3c24xx_gpios' was not declared. Should it be static?
Signed-off-by: NBen Dooks <ben@simtec.co.uk>
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

arch/arm/plat-s3c24xx/gpiolib.c

@@ -19,7 +19,7 @@
 #include <linux/io.h>
 #include <linux/gpio.h>
 
-#include <plat/gpio-core.h>
+#include <mach/gpio-core.h>
 #include <mach/hardware.h>
 #include <asm/irq.h>