arm: add initial support for Amlogic Meson and ODROID-C2

This adds platform code for the Amlogic Meson GXBaby (S905) SoC and a
board definition for ODROID-C2. This initial submission only supports
UART and Ethernet (through the existing Designware driver). DTS files
are the ones submitted to Linux arm-soc for 4.7 [1].

[1] https://patchwork.ozlabs.org/patch/603583/

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-meson/Kconfig b/arch/arm/mach-meson/Kconfig
new file mode 100644
index 0000000..77d3cfe
--- /dev/null
+++ b/arch/arm/mach-meson/Kconfig
@@ -0,0 +1,31 @@
+if ARCH_MESON
+
+config MESON_GXBB
+	bool "Support Meson GXBaby"
+	select ARM64
+	select DM
+	select DM_SERIAL
+	help
+	  The Amlogic Meson GXBaby (S905) is an ARM SoC with a
+	  quad-core Cortex-A53 CPU and a Mali-450 GPU.
+
+if MESON_GXBB
+
+config TARGET_ODROID_C2
+	bool "ODROID-C2"
+	help
+	  ODROID-C2 is a single board computer based on Meson GXBaby
+	  with 2 GiB of RAM, Gigabit Ethernet, HDMI, 4 USB, micro-SD
+	  slot, eMMC, IR receiver and a 40-pin GPIO header.
+
+endif
+
+config SYS_SOC
+	default "meson"
+
+config SYS_MALLOC_F_LEN
+	default 0x1000
+
+source "board/hardkernel/odroid-c2/Kconfig"
+
+endif