Split duart configuration as device tree file. Move /chosen node
out of board commone device tree. Convert ls1021aqds nor and SD
configurations to driver model support (qspi already uses DM).
Enable ns16550 DM serial driver for nor configurations.

Signed-off-by: York Sun
CC: Alison Wang
CC: Bin Meng
Reviewed-by: Bin Meng
Reviewed-by: Alison Wang