gpio: samsung: skip gpiolib registration if pinctrl support is enabled for exynos5250

Skip exynos5250 gpiolib registration if pinctrl support for exynos5250
is enabled.

Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>