configs: convert NXP LS1028A RDB and QDS to DM_SERIAL

configs: convert NXP LS1028A RDB and QDS to DM_SERIAL

Since the device trees are more or less synchronized with Linux, the
only necessary changes are to enable CONFIG_DM_SERIAL and the DM_SERIAL
driver for ns16550 (ns16550.c rather than serial_ns16550.c).

ls1028aqds_tfa_lpuart_defconfig already uses DM_SERIAL for the LPUART
driver, so I didn't touch that.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>