Move CONFIG_OF_LIBFDT to Kconfig

Move this option to Kconfig and tidy up existing boards.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/da850evm_direct_nor_defconfig b/configs/da850evm_direct_nor_defconfig
index d8c002f..7aba5c4 100644
--- a/configs/da850evm_direct_nor_defconfig
+++ b/configs/da850evm_direct_nor_defconfig
@@ -8,3 +8,4 @@
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_SYS_NS16550=y
+CONFIG_OF_LIBFDT=y