arm: MediaTek: add basic support for MT7623 boards

This adds a general board file based on MT7623 SoCs from MediaTek.

As this u-boot is loaded by MTK proprietary preloader, there is no
low level initializtion codes.

Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Tested-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-mediatek/Kconfig b/arch/arm/mach-mediatek/Kconfig
index d2ada97..7a733e9 100644
--- a/arch/arm/mach-mediatek/Kconfig
+++ b/arch/arm/mach-mediatek/Kconfig
@@ -9,6 +9,18 @@
 choice
 	prompt "MediaTek board select"
 
+config TARGET_MT7623
+	bool "MediaTek MT7623 SoC"
+	select CPU_V7A
+	select ARCH_MISC_INIT
+	help
+	  The MediaTek MT7623 is a ARM-based SoC with a quad-core Cortex-A7
+	  including NEON and GPU, Mali-450 graphics, several DDR3 options,
+	  crypto engine, built-in Wi-Fi / Bluetooth combo chip, JPEG decoder,
+	  video interfaces supporting HDMI and MIPI, and video codec support.
+	  Peripherals include Gigabit Ethernet, switch, USB3.0 and OTG, PCIe,
+	  I2S, PCM, S/PDIF, UART, SPI, I2C, IR TX/RX, and PWM.
+
 config TARGET_MT7629
 	bool "MediaTek MT7629 SoC"
 	select CPU_V7A
@@ -21,6 +33,7 @@
 
 endchoice
 
+source "board/mediatek/mt7623/Kconfig"
 source "board/mediatek/mt7629/Kconfig"
 
 endif