configs: ls1043ardb: enable DM_SERIAL
As the serial devices are configured in the device tree, enable
DM_SERIAL in the ls1043ardb defconfigs.
Signed-off-by: Camelia Groza <camelia.groza@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>