board: tbs2910: Add device tree

... as preparation for additional driver model coonversions.

We use CONFIG_OF_EMBED here to keep u-boot.imx as final binary name. So we
maintain compatibility with the original TBS u-boot and available HOWTOs
for u-boot updates.

Signed-off-by: Soeren Moch <smoch@web.de>
diff --git a/configs/tbs2910_defconfig b/configs/tbs2910_defconfig
index 70a3e18..3cc68eb 100644
--- a/configs/tbs2910_defconfig
+++ b/configs/tbs2910_defconfig
@@ -36,6 +36,9 @@
 CONFIG_CMD_FAT=y
 CONFIG_CMD_FS_GENERIC=y
 CONFIG_EFI_PARTITION=y
+CONFIG_OF_CONTROL=y
+CONFIG_OF_EMBED=y
+CONFIG_DEFAULT_DEVICE_TREE="imx6q-tbs2910"
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_DM=y
 CONFIG_DWC_AHSATA=y
@@ -55,5 +58,4 @@
 CONFIG_CI_UDC=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_VIDEO=y
-CONFIG_OF_LIBFDT=y
 # CONFIG_EFI_LOADER is not set