ls102xa: ddr4: Use LPUART as console output to verify DCU driver

On QDS board with DDR4 DIMM, LPUART is used as console
output to verify DCU driver. This patch adds
ls1021aqds_ddr4_nor_lpuart_defconfig for this support.

Signed-off-by: Alison Wang <alison.wang@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/ls1021aqds/MAINTAINERS b/board/freescale/ls1021aqds/MAINTAINERS
index 661526b..820d322 100644
--- a/board/freescale/ls1021aqds/MAINTAINERS
+++ b/board/freescale/ls1021aqds/MAINTAINERS
@@ -5,6 +5,7 @@
 F:	include/configs/ls1021aqds.h
 F:	configs/ls1021aqds_nor_defconfig
 F:	configs/ls1021aqds_ddr4_nor_defconfig
+F:	configs/ls1021aqds_ddr4_nor_lpuart_defconfig
 F:	configs/ls1021aqds_nor_SECURE_BOOT_defconfig
 F:	configs/ls1021aqds_nor_lpuart_defconfig
 F:	configs/ls1021aqds_sdcard_defconfig