sunxi: a53: add support for Olimex A64-Olinuxino

sunxi: a53: add support for Olimex A64-Olinuxino

Specifications:

 SoC: Allwinner A64 (1.2 GHz Quad-Core ARM Cortex-A53 64-bit)
 RAM: 1GB or 2GB RAM DDR3L @ 672Mhz
 Flash: 0/4/16GB eMMC flash memory for storage and boot
 MicroSD card connector for cards up to 32GB
 Debug: serial UART debug header with 0.1" pins
 Wired connectivity: 10/100/1000Mbps GbE Ethernet
 Wireless connectivity: on-board RTL8723BS 1T1R 802.11bgn WiFi and
                        Bluetooth 4.0 module with built-in antenna
                        (only available in the A64-OLinuXino-1G4GW)

Flashing instructions:

 Standard sunxi SD card installation procedure - copy image to SD card,
 insert in into SD card slot on the device and boot.

Known issues:

 Wireless doesn't work properly via netifd.

Signed-off-by: Petr Štetiar <ynezz@true.cz>