It's safe to empty the plat-samsung/incude/plat/gpio-fns.h header
now when all users of those functions have been converted to
generic gpiolib API or to s3c_gpio_cfg().

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: NSylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>