arm: MediaTek: add basic support for MT7629 boards

This adds a general board file based on MT7629 SoCs from MediaTek.

Apart from the generic parts (cpu) we add some low level init codes
and initialize the early clocks.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-mediatek/Kconfig b/arch/arm/mach-mediatek/Kconfig
new file mode 100644
index 0000000..d2ada97
--- /dev/null
+++ b/arch/arm/mach-mediatek/Kconfig
@@ -0,0 +1,26 @@
+if ARCH_MEDIATEK
+
+config SYS_SOC
+	default "mediatek"
+
+config SYS_VENDOR
+	default "mediatek"
+
+choice
+	prompt "MediaTek board select"
+
+config TARGET_MT7629
+	bool "MediaTek MT7629 SoC"
+	select CPU_V7A
+	select SPL
+	select ARCH_MISC_INIT
+	help
+	  The MediaTek MT7629 is a ARM-based SoC with a dual-core Cortex-A7
+	  including DDR3, crypto engine, 3x3 11n/ac Wi-Fi, Gigabit Ethernet,
+	  switch, USB3.0, PCIe, UART, SPI, I2C and PWM.
+
+endchoice
+
+source "board/mediatek/mt7629/Kconfig"
+
+endif