uboot-imx

db820c: add qualcomm dragonboard 820C support

This commit adds support for 96Boards Dragonboard820C.

The board is based on APQ8086 Qualcomm Soc, complying with the
96Boards specification.

Features
 - 4x Kyro CPU (64 bit) up to 2.15GHz
 - USB2.0
 - USB3.0
 - ISP
 - Qualcomm Hexagon DSP
 - SD 3.0 (UHS-I)
 - UFS 2.0
 - Qualcomm Adreno 530 GPU
 - GPS
 - BT 4.2
 - Wi-Fi 2.4GHz, 5GHz (802.11ac)
 - PCIe 2.0
 - MIPI-CSI, MIPI-DSI
 - I2S

U-Boot boots chained from LK (LK implements the fastboot protocol) in
64-bit mode.

For detailed build instructions see readme.txt in the board directory.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>