ARM: EXYNOS: Enable pinctrl driver support for EXYNOS4 device tree enabled platform

This enables support for Samsung and EXYNOS4 pinctrl driver for device
tree enabled EXYNOS4 platforms.

Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>