colibri_imx6: migrate to using device tree

Migrate to using device tree required for further driver model
integration.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
diff --git a/configs/colibri_imx6_defconfig b/configs/colibri_imx6_defconfig
index 84fa427..47e05b0 100644
--- a/configs/colibri_imx6_defconfig
+++ b/configs/colibri_imx6_defconfig
@@ -45,6 +45,8 @@
 CONFIG_CMD_USB_MASS_STORAGE=y
 CONFIG_CMD_BMP=y
 CONFIG_CMD_CACHE=y
+CONFIG_OF_CONTROL=y
+CONFIG_DEFAULT_DEVICE_TREE="imx6-colibri"
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG=y
 CONFIG_DFU_MMC=y
@@ -64,5 +66,4 @@
 CONFIG_USB_HOST_ETHER=y
 CONFIG_VIDEO=y
 CONFIG_FAT_WRITE=y
-CONFIG_OF_LIBFDT=y
 CONFIG_OF_LIBFDT_OVERLAY=y