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/neo_defconfig b/configs/neo_defconfig
index 2dd2f6e..1bbaf6b 100644
--- a/configs/neo_defconfig
+++ b/configs/neo_defconfig
@@ -10,6 +10,7 @@
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_VERSION_VARIABLE=y
 # CONFIG_DISPLAY_BOARDINFO is not set
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y
 # CONFIG_CMD_ELF is not set
 CONFIG_CMD_ASKENV=y