armv8: ls1028a: Add secure boot defconfig

Add secure boot defconfig for ls1028aqds and ls1028ardb boards.

Signed-off-by: Yuantian Tang <andy.tang@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/board/freescale/ls1028a/MAINTAINERS b/board/freescale/ls1028a/MAINTAINERS
index 6f1a95e..2c28825 100644
--- a/board/freescale/ls1028a/MAINTAINERS
+++ b/board/freescale/ls1028a/MAINTAINERS
@@ -19,3 +19,13 @@
 F:	include/configs/ls1028a_common.h
 F:	include/configs/ls1028ardb.h
 F:	configs/ls1028ardb_tfa_defconfig
+
+LS1028AQDS_SECURE_BOOT BOARD
+M:	Tang Yuantian <andy.tang@nxp.com>
+S:	Maintained
+F:	configs/ls1028aqds_tfa_SECURE_BOOT_defconfig
+
+LS1028ARDB_SECURE_BOOT BOARD
+M:	Tang Yuantian <andy.tang@nxp.com>
+S:	Maintained
+F:	configs/ls1028ardb_tfa_SECURE_BOOT_defconfig