bx50v3: Enable CONFIG_OF_LIBFDT in defconfig

As of commit 69e173eb57d1f4848f070c83456096ba5d2ba1b4, CONFIG_OF_LIBFDT
needs to be selected in defconfig instead of board specific header file.
Hence enable CONFIG_OF_LIBFDT in defconfig.

Signed-off-by: Akshay Bhat <akshay.bhat@timesys.com>
diff --git a/configs/ge_b450v3_defconfig b/configs/ge_b450v3_defconfig
index 02873ce..24ef9e8 100644
--- a/configs/ge_b450v3_defconfig
+++ b/configs/ge_b450v3_defconfig
@@ -6,3 +6,4 @@
 CONFIG_CMD_GPIO=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_STMICRO=y
+CONFIG_OF_LIBFDT=y