arm: exynos: add support for Exynos7420 SoC

Add support for Exynos7420 SoC. The Exynos7420 SoC has four Cortex-A57
and four Cortex-A53 CPUs and includes various peripheral controllers.

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 28a6a60..0a6cb33 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -20,6 +20,14 @@
 	  Cortex-A7 CPU in big.LITTLE configuration). There are multiple SoCs
 	  in this family including Exynos5250, Exynos5420 and Exynos5800.
 
+config ARCH_EXYNOS7
+	bool "Exynos7 SoC family"
+	select ARM64
+	help
+	  Samsung Exynos7 SoC family are based on ARM Cortex-A57 CPU or
+	  Cortex-A53 CPU (and some in a big.LITTLE configuration). There are
+	  multiple SoCs in this family including Exynos7420.
+
 endchoice
 
 if ARCH_EXYNOS4