config: Move CONFIG_DEFAULT_FDT_FILE to defconfigs

- Add DEFAULT_FDT_FILE kconfig entry
- Move CONFIG_DEFAULT_FDT_FILE from include/configs to defconfigs

Cc: Tom Rini <trini@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/configs/ge_b450v3_defconfig b/configs/ge_b450v3_defconfig
index 8577167..4a5322d 100644
--- a/configs/ge_b450v3_defconfig
+++ b/configs/ge_b450v3_defconfig
@@ -1,6 +1,7 @@
 CONFIG_ARM=y
 CONFIG_ARCH_MX6=y
 CONFIG_TARGET_GE_B450V3=y
+CONFIG_DEFAULT_FDT_FILE="/boot/imx6q-b450v3.dtb"
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_BOOTDELAY=1
 CONFIG_HUSH_PARSER=y