arm64: vexpress: Enable ARMv8 RTSM model (SoC) support

This patch adds the necessary Kconfig entries to enable support for the
ARMv8 software model (Versatile Express platform) together with the
defconfig update.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9b6d19f..73b6e76 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -99,7 +99,16 @@
 
 source "kernel/Kconfig.freezer"
 
-menu "System Type"
+menu "Platform selection"
+
+config ARCH_VEXPRESS
+	bool "ARMv8 software model (Versatile Express)"
+	select ARCH_REQUIRE_GPIOLIB
+	select COMMON_CLK_VERSATILE
+	select VEXPRESS_CONFIG
+	help
+	  This enables support for the ARMv8 software model (Versatile
+	  Express).
 
 endmenu