ARM: SAMSUNG: Fix on inclusion mach/gpio.h on gpiolib.c

Fix on inclusion mach/gpio.h on plat-samsung/gpiolib.c
since new C preprocessor directives.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Ben Dooks <ben-linux@fluff.org>
[kgene.kim@samsung.com: minor title and message fix]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>