pinctrl: samsung: Fix missing OF and GPIOLIB dependency on S3C24xx and S3C64xx

All Samsung pinctrl drivers select common part - PINCTRL_SAMSUNG which uses
both OF and GPIOLIB inside.  However only Exynos drivers depend on these,
therefore after enabling COMPILE_TEST, on x86_64 build of S3C64xx driver
failed:

    drivers/pinctrl/samsung/pinctrl-samsung.c: In function ‘samsung_gpiolib_register’:
    drivers/pinctrl/samsung/pinctrl-samsung.c:969:5: error: ‘struct gpio_chip’ has no member named ‘of_node’
       gc->of_node = bank->of_node;
         ^

Rework the dependencies so all Samsung drivers and common
PINCTRL_SAMSUNG part depend on OF_GPIO (which is default yes if GPIOLIB
and OF are enabled).

Reported-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>