am3517_evm: add FIT support

Enable DTS support (CONFIG_OF_LIBFDT) and select
CONFIG_FIT in defconfig.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/am3517_evm_defconfig b/configs/am3517_evm_defconfig
index 4589b30..c72d29e 100644
--- a/configs/am3517_evm_defconfig
+++ b/configs/am3517_evm_defconfig
@@ -2,6 +2,7 @@
 CONFIG_OMAP34XX=y
 CONFIG_TARGET_AM3517_EVM=y
 CONFIG_SPL=y
+CONFIG_FIT=y
 # CONFIG_CMD_IMI is not set
 # CONFIG_CMD_IMLS is not set
 # CONFIG_CMD_FLASH is not set