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/P4080DS_SECURE_BOOT_defconfig b/configs/P4080DS_SECURE_BOOT_defconfig
index 7b41915..afe0594 100644
--- a/configs/P4080DS_SECURE_BOOT_defconfig
+++ b/configs/P4080DS_SECURE_BOOT_defconfig
@@ -8,6 +8,7 @@
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_OF_STDOUT_VIA_ALIAS=y
 CONFIG_BOOTDELAY=10
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_GREPENV=y
 CONFIG_CMD_MMC=y