sunxi: H616: add support for YuzukiHD Chameleon board

sunxi: H616: add support for YuzukiHD Chameleon board

The Chameleon board is an OpenHardware devboard made by YuzukiTsuru,
featuring an Allwinner H616 SoC. The form factor resembles the Raspberry
Pi Model A boards, though it differs significantly in its features.
Apart from the usual peripherals of those kind of boards (SD card, eMMC,
WiFi, HDMI), it features four USB-C 2.0 ports.

Add a defconfig for the board, the DRAM parameters have been extracted
from the firmware shipped with the board.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>