arm: imx8m: imx8mm-cl-iot-gate: detect extension board

Extension boards can be added to Compulab's iot-gate-imx8mm.
We implement extension board manager for detecting the extension
boards.

Signed-off-by: Uri Mashiach <uri.mashiach@compulab.co.il>
Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Cc: uboot-imx <uboot-imx@nxp.com>
diff --git a/arch/arm/mach-imx/imx8m/Kconfig b/arch/arm/mach-imx/imx8m/Kconfig
index d6a8690..6c20d08 100644
--- a/arch/arm/mach-imx/imx8m/Kconfig
+++ b/arch/arm/mach-imx/imx8m/Kconfig
@@ -153,6 +153,7 @@
 	select IMX8MM
 	select SUPPORT_SPL
 	select IMX8M_LPDDR4
+	select SUPPORT_EXTENSION_SCAN
 
 config TARGET_IMX8MM_CL_IOT_GATE_OPTEE
 	bool "CompuLab iot-gate-imx8 with optee support"
@@ -160,6 +161,7 @@
 	select IMX8MM
 	select SUPPORT_SPL
 	select IMX8M_LPDDR4
+	select SUPPORT_EXTENSION_SCAN
 endchoice
 
 source "board/beacon/imx8mm/Kconfig"