gpio: samsung: skip gpio lib registration for EXYNOS5440

Since exynos5440 can support pinctrl so skip the legacy
gpiolib registration. If not, happens following.

WARNING: at drivers/gpio/gpio-samsung.c:3102 samsung_gpiolib_init+0x68/0x8c()
Unknown SoC in gpio-samsung, no GPIOs added
Acked-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-samsung.c

@@ -3025,6 +3025,7 @@ static __init int samsung_gpiolib_init(void)
 	static const struct of_device_id exynos_pinctrl_ids[] = {
 		{ .compatible = "samsung,pinctrl-exynos4210", },
 		{ .compatible = "samsung,pinctrl-exynos4x12", },
+		{ .compatible = "samsung,pinctrl-exynos5440", },
 	};
 	for_each_matching_node(pctrl_np, exynos_pinctrl_ids)
 		if (pctrl_np && of_device_is_available(pctrl_np))