board: qualcomm: Add support for dragonboard845c

Add support for 96Boards Dragonboard 845C aka Robotics RB3 development
platform. This board complies with 96Boards Open Platform Specifications.

Features:
- Qualcomm Snapdragon SDA845 SoC
- 4GiB RAM
- 64GiB UFS drive

U-boot is chain loaded by ABL in 64-bit mode as part of boot.img.
For detailed build and boot instructions, refer to
doc/board/qualcomm/sdm845.rst, board: dragonboard845c.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/board/qualcomm/dragonboard845c/MAINTAINERS b/board/qualcomm/dragonboard845c/MAINTAINERS
new file mode 100644
index 0000000..e555953
--- /dev/null
+++ b/board/qualcomm/dragonboard845c/MAINTAINERS
@@ -0,0 +1,6 @@
+Qualcomm Robotics RB3 Development Platform (dragonboard845c)
+M:	Sumit Garg <sumit.garg@linaro.org>
+S:	Maintained
+F:	board/qualcomm/dragonboard845c/
+F:	include/configs/dragonboard845c.h
+F:	configs/dragonboard845c_defconfig