Convert CONFIG_BOARD_EARLY_INIT_F to Kconfig

This converts the following to Kconfig:
   CONFIG_BOARD_EARLY_INIT_F

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/titanium_defconfig b/configs/titanium_defconfig
index 478eba9..d772ec5 100644
--- a/configs/titanium_defconfig
+++ b/configs/titanium_defconfig
@@ -3,6 +3,7 @@
 CONFIG_TARGET_TITANIUM=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/barco/titanium/imximage.cfg"
 CONFIG_BOOTDELAY=3
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="Titanium > "
 CONFIG_CMD_BOOTZ=y