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/bf609-ezkit_defconfig b/configs/bf609-ezkit_defconfig
index 8fc0bf9..0b4129e 100644
--- a/configs/bf609-ezkit_defconfig
+++ b/configs/bf609-ezkit_defconfig
@@ -14,6 +14,7 @@
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_EXT2=y
 CONFIG_CMD_FAT=y
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_ATMEL=y
 CONFIG_SPI_FLASH_EON=y