gpio/exynos: Fix compiler warning in gpio-samsung.c file

Fixes the following warning when "SAMSUNG EXYNOS5" is not selected:

warning: ‘exynos5_gpios_1’ defined but not used [-Wunused-variable]
warning: ‘exynos5_gpios_2’ defined but not used [-Wunused-variable]
warning: ‘exynos5_gpios_3’ defined but not used [-Wunused-variable]
warning: ‘exynos5_gpios_4’ defined but not used [-Wunused-variable]

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>