armv8: fsl-layerscape: Fix SECURE_BOOT config

Without a prompt in Kconfig, SECURE_BOOT cannot be selected by
defconfig. The option was dropped unintentionally when defconfig
files were cleaned up. Three targets were impacted
ls1043ardb_SECURE_BOOT, ls2080ardb_SECURE_BOOT,
ls2080aqds_SECURE_BOOT.

Signed-off-by: York Sun <york.sun@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/ls2080aqds_SECURE_BOOT_defconfig b/configs/ls2080aqds_SECURE_BOOT_defconfig
index 047c2c1..c741bf9 100644
--- a/configs/ls2080aqds_SECURE_BOOT_defconfig
+++ b/configs/ls2080aqds_SECURE_BOOT_defconfig
@@ -1,5 +1,6 @@
 CONFIG_ARM=y
 CONFIG_TARGET_LS2080AQDS=y
+CONFIG_SECURE_BOOT=y
 CONFIG_DEFAULT_DEVICE_TREE="fsl-ls2080a-qds"
 # CONFIG_SYS_MALLOC_F is not set
 CONFIG_FIT=y