sun50i: a64: Add initial NanoPi A64 support

NanoPi A64 is a new board of high performance with low cost
designed by FriendlyElec., using the Allwinner A64 SOC.

Nanopi A64 features
- Allwinner A64, 64-bit Quad-core Cortex-A53@648MHz to 1.152GHz, DVFS
- 1GB DDR3 RAM
- MicroSD
- Gigabit Ethernet (RTL8211E)
- Wi-Fi 802.11b/g/n
- IR receiver
- Audio In/Out
- Video In/Out
- Serial Debug Port
- microUSB 5V 2A DC power-supply

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/board/sunxi/MAINTAINERS b/board/sunxi/MAINTAINERS
index ed4d4c3..3b8d544 100644
--- a/board/sunxi/MAINTAINERS
+++ b/board/sunxi/MAINTAINERS
@@ -272,6 +272,11 @@
 S:	Maintained
 F:	configs/nanopi_neo_air_defconfig
 
+NANOPI-A64 BOARD
+M:	Jagan Teki <jagan@amarulasolutions.com>
+S:	Maintained
+F:	configs/nanopi_a64_defconfig
+
 NINTENDO NES CLASSIC EDITION BOARD
 M:	FUKAUMI Naoki <naobsd@gmail.com>
 S:	Maintained