imx8mn-evk: switch to use binman

Use binman to pack images.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/mach-imx/imx8m/Kconfig b/arch/arm/mach-imx/imx8m/Kconfig
index be697bd..390ead9 100644
--- a/arch/arm/mach-imx/imx8m/Kconfig
+++ b/arch/arm/mach-imx/imx8m/Kconfig
@@ -53,6 +53,7 @@
 
 config TARGET_IMX8MN_EVK
 	bool "imx8mn LPDDR4 EVK board"
+	select BINMAN
 	select IMX8MN
 	select SUPPORT_SPL
 	select IMX8M_LPDDR4