gpio/exynos: Fix compiler warnings when non-exynos machines are selected

Fixes the following compiler warnings:

drivers/gpio/gpio-samsung.c: In function ‘samsung_gpiolib_init’:
drivers/gpio/gpio-samsung.c:2980:1: warning: label ‘err_ioremap1’ defined but not used [-Wunused-label]
drivers/gpio/gpio-samsung.c:2978:1: warning: label ‘err_ioremap2’ defined but not used [-Wunused-label]
drivers/gpio/gpio-samsung.c:2976:1: warning: label ‘err_ioremap3’ defined but not used [-Wunused-label]
drivers/gpio/gpio-samsung.c:2974:1: warning: label ‘err_ioremap4’ defined but not used [-Wunused-label]
drivers/gpio/gpio-samsung.c:2722:55: warning: unused variable ‘gpio_base4’ [-Wunused-variable]

drivers/gpio/gpio-samsung.c:455:32: warning: ‘exynos_gpio_cfg’ defined but not used [-Wunused-variable]
drivers/gpio/gpio-samsung.c:2126:33: warning: ‘exynos4_gpios_1’ defined but not used [-Wunused-variable]
drivers/gpio/gpio-samsung.c:2228:33: warning: ‘exynos4_gpios_2’ defined but not used [-Wunused-variable]
drivers/gpio/gpio-samsung.c:2373:33: warning: ‘exynos4_gpios_3’ defined but not used [-Wunused-variable]

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