sun6i: Add new board Merrii Hummingbird A31

The Merrii Hummingbird A31 is a A31 based development board with 1G
RAM, 8G NAND, AP6210 WiFi+BT, gigabit ethernet, USB OTG, 2 USB 2.0
ports connected to a USB hub chip, HDMI, VGA, TV and stereo in/out.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig
index f7da704..88f09fb 100644
--- a/board/sunxi/Kconfig
+++ b/board/sunxi/Kconfig
@@ -111,6 +111,10 @@
 	bool "CUBIETRUCK"
 	depends on MACH_SUN7I
 
+config TARGET_HUMMINGBIRD_A31
+	bool "HUMMINGBIRD_A31"
+	depends on MACH_SUN6I
+
 config TARGET_IPPO_Q8H_V5
 	bool "IPPO_Q8H_V5"
 	depends on MACH_SUN8I