gpio: Fix gpio-exynos4 build fails in mainline

After the GPIO driver move, some symbols became selectable when they
shouldn't be.  Tighten the dependencies.
Reported-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

drivers/gpio/Kconfig

@@ -88,29 +88,29 @@ config GPIO_IT8761E
 
 config GPIO_EXYNOS4
 	bool "Samsung Exynos4 GPIO library support"
-	default y if CPU_EXYNOS4210
-	depends on ARM
+	default y
+	depends on ARM && CPU_EXYNOS4210
 	help
 	  Say yes here to support Samsung Exynos4 series SoCs GPIO library
 
 config GPIO_PLAT_SAMSUNG
 	bool "Samsung SoCs GPIO library support"
-	default y if SAMSUNG_GPIOLIB_4BIT
-	depends on ARM
+	default y
+	depends on ARM && SAMSUNG_GPIOLIB_4BIT
 	help
 	  Say yes here to support Samsung SoCs GPIO library
 
 config GPIO_S5PC100
 	bool "Samsung S5PC100 GPIO library support"
-	default y if CPU_S5PC100
-	depends on ARM
+	default y
+	depends on ARM && CPU_S5PC100
 	help
 	  Say yes here to support Samsung S5PC100 SoCs GPIO library
 
 config GPIO_S5PV210
 	bool "Samsung S5PV210/S5PC110 GPIO library support"
-	default y if CPU_S5PV210
-	depends on ARM
+	default y
+	depends on ARM && CPU_S5PV210
 	help
 	  Say yes here to support Samsung S5PV210/S5PC110 SoCs GPIO library