LS102xA is an ARMv7 implementation. This patch is to add
basic support for LS1021AQDS board.
One DDR controller
DUART1 is used as the console

For the detail board information, please refer to README.

Signed-off-by: Alison Wang
Signed-off-by: Jason Jin
Signed-off-by: York Sun
Signed-off-by: Yuan Yao
Signed-off-by: Prabhakar Kushwaha