sunxi: add defconfig for nanopi_duo2

FriendlyElec NanoPi Duo2 is a tiny SBC with Allwinner H3 and
Ampak AP6212 WiFi module. The device-tree for it is already
available in u-boot source tree. Add a default config for it.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
[Andre: enable USB gadgets]
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/configs/nanopi_duo2_defconfig b/configs/nanopi_duo2_defconfig
new file mode 100644
index 0000000..beb2f92
--- /dev/null
+++ b/configs/nanopi_duo2_defconfig
@@ -0,0 +1,12 @@
+CONFIG_ARM=y
+CONFIG_ARCH_SUNXI=y
+CONFIG_DEFAULT_DEVICE_TREE="sun8i-h3-nanopi-duo2"
+CONFIG_SPL=y
+CONFIG_MACH_SUN8I_H3=y
+CONFIG_DRAM_CLK=408
+# CONFIG_VIDEO_DE2 is not set
+# CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
+CONFIG_CONSOLE_MUX=y
+CONFIG_USB_EHCI_HCD=y
+CONFIG_USB_OHCI_HCD=y
+CONFIG_USB_MUSB_GADGET=y