sun50i: a64: Add initial NanoPi A64 support

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>