arm64: mediatek: Add MT8173 SoC Kconfig and defconfig

Add MT8173 arm64 Kconfig and defconfig files

Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
Acked-by: Arnd Bergmann <arnd at arndb.de>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b1f9a20..e627ead 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -148,6 +148,12 @@
 
 menu "Platform selection"
 
+config ARCH_MEDIATEK
+	bool "Mediatek MT65xx & MT81xx ARMv8 SoC"
+	select ARM_GIC
+	help
+	  Support for Mediatek MT65xx & MT81xx ARMv8 SoCs
+
 config ARCH_SEATTLE
 	bool "AMD Seattle SoC Family"
 	help