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/hikey_defconfig b/configs/hikey_defconfig
index 539c7d3..8dd330a 100644
--- a/configs/hikey_defconfig
+++ b/configs/hikey_defconfig
@@ -5,6 +5,7 @@
 CONFIG_DISTRO_DEFAULTS=y
 # CONFIG_DISPLAY_CPUINFO is not set
 # CONFIG_DISPLAY_BOARDINFO is not set
+CONFIG_BOARD_EARLY_INIT_F=y
 # CONFIG_CMD_IMLS is not set
 CONFIG_CMD_MMC=y
 CONFIG_CMD_USB=y