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/configs/defconfig b/arch/arm64/configs/defconfig
index dd301be..ed84d21 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -32,6 +32,7 @@
 CONFIG_MODULE_UNLOAD=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
+CONFIG_ARCH_MEDIATEK=y
 CONFIG_ARCH_THUNDER=y
 CONFIG_ARCH_VEXPRESS=y
 CONFIG_ARCH_XGENE=y
@@ -87,6 +88,7 @@
 CONFIG_LEGACY_PTY_COUNT=16
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_8250_MT6577=y
 CONFIG_SERIAL_AMBA_PL011=y
 CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y