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>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index bbc4f47..ee78cdd 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -211,7 +211,8 @@
 	fsl-ls1012a-rdb.dtb \
 	fsl-ls1012a-frdm.dtb
 
-dtb-$(CONFIG_ARCH_SNAPDRAGON) += dragonboard410c.dtb
+dtb-$(CONFIG_TARGET_DRAGONBOARD410C) += dragonboard410c.dtb
+dtb-$(CONFIG_TARGET_DRAGONBOARD820C) += dragonboard820c.dtb
 
 dtb-$(CONFIG_STM32F4) += stm32f429-disco.dtb \
 	stm32f469-disco.dtb