powerpc: Enable device tree support for T4240RDB

Add device tree for T4240RDB board and enable CONFIG_OF_CONTROL
so that device tree can be compiled.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/configs/T4240RDB_SDCARD_defconfig b/configs/T4240RDB_SDCARD_defconfig
index 9405755..b82de5c 100644
--- a/configs/T4240RDB_SDCARD_defconfig
+++ b/configs/T4240RDB_SDCARD_defconfig
@@ -35,6 +35,8 @@
 CONFIG_MP=y
 CONFIG_CMD_EXT2=y
 CONFIG_CMD_FAT=y
+CONFIG_OF_CONTROL=y
+CONFIG_DEFAULT_DEVICE_TREE="t4240rdb"
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_FSL_CAAM=y
 CONFIG_FSL_ESDHC=y
@@ -57,4 +59,3 @@
 CONFIG_FSL_ESPI=y
 CONFIG_USB=y
 CONFIG_USB_STORAGE=y
-CONFIG_OF_LIBFDT=y