configs: ls1028a: enable OF_LIBFDT_OVERLAY

LS1028A QDS board supports multiple combinations of SerDes protocols and
multiple add-on cards with Ethernet PHYs.  Some of them require specific
configuration in Linux DT, and the plan is to use DT overlays for them.

Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/configs/ls1028aqds_tfa_SECURE_BOOT_defconfig b/configs/ls1028aqds_tfa_SECURE_BOOT_defconfig
index b14dc59..cd3836a 100644
--- a/configs/ls1028aqds_tfa_SECURE_BOOT_defconfig
+++ b/configs/ls1028aqds_tfa_SECURE_BOOT_defconfig
@@ -71,4 +71,5 @@
 CONFIG_WDT=y
 CONFIG_WDT_SP805=y
 CONFIG_RSA=y
+CONFIG_OF_LIBFDT_OVERLAY=y
 CONFIG_EFI_LOADER_BOUNCE_BUFFER=y