imx8qxp_mek: switch to use container image

Because FIT could not be used for AHAB secure boot on i.MX8,
so switch to use container image that could let SPL verify
ATF and U-Boot with AHAB.

Note: The AHAB related code has not been added.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/configs/imx8qxp_mek_defconfig b/configs/imx8qxp_mek_defconfig
index f4cc86e..580d757 100644
--- a/configs/imx8qxp_mek_defconfig
+++ b/configs/imx8qxp_mek_defconfig
@@ -7,15 +7,14 @@
 CONFIG_SPL_LIBCOMMON_SUPPORT=y
 CONFIG_SPL_LIBGENERIC_SUPPORT=y
 CONFIG_SYS_MALLOC_F_LEN=0x4000
+CONFIG_SPL_LOAD_IMX_CONTAINER=y
+CONFIG_IMX_CONTAINER_CFG="board/freescale/imx8qxp_mek/uboot-container.cfg"
 CONFIG_TARGET_IMX8QXP_MEK=y
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL_SERIAL_SUPPORT=y
 CONFIG_SPL_DRIVERS_MISC_SUPPORT=y
 CONFIG_NR_DRAM_BANKS=3
 CONFIG_SPL=y
-CONFIG_FIT=y
-CONFIG_SPL_LOAD_FIT=y
-CONFIG_SPL_FIT_GENERATOR="arch/arm/mach-imx/mkimage_fit_atf.sh"
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/imx8qxp_mek/imximage.cfg"
 CONFIG_BOOTDELAY=3
 CONFIG_LOG=y