imx8mm_venice: switch to use binman to pack images

Use binman to pack images.

Note that imx8mm_venice supports several boards via multiple DTB's thus
in the fit node we must use:
- fit,fdt-list = "of-list"
- fdt-SEQ
- config-SEQ

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/arch/arm/mach-imx/imx8m/Kconfig b/arch/arm/mach-imx/imx8m/Kconfig
index d630a73..d6a8690 100644
--- a/arch/arm/mach-imx/imx8m/Kconfig
+++ b/arch/arm/mach-imx/imx8m/Kconfig
@@ -73,6 +73,7 @@
 
 config TARGET_IMX8MM_VENICE
 	bool "Support Gateworks Venice iMX8M Mini module"
+	select BINMAN
 	select IMX8MM
 	select SUPPORT_SPL
 	select IMX8M_LPDDR4