configs: ls208x: enable DM_SERIAL

Now that the DT nodes for the serial devices are in place for these
boards, enable DM_SERIAL in the associated configs.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/configs/ls2088ardb_tfa_SECURE_BOOT_defconfig b/configs/ls2088ardb_tfa_SECURE_BOOT_defconfig
index 1dd7c1d..f110bee 100644
--- a/configs/ls2088ardb_tfa_SECURE_BOOT_defconfig
+++ b/configs/ls2088ardb_tfa_SECURE_BOOT_defconfig
@@ -100,8 +100,10 @@
 CONFIG_DM_RTC=y
 CONFIG_RTC_DS3231=y
 CONFIG_DM_SCSI=y
+CONFIG_SPECIFY_CONSOLE_INDEX=y
 CONFIG_CONS_INDEX=2
-CONFIG_SYS_NS16550_SERIAL=y
+CONFIG_DM_SERIAL=y
+CONFIG_SYS_NS16550=y
 CONFIG_SPI=y
 CONFIG_DM_SPI=y
 CONFIG_FSL_DSPI=y