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/P1023RDB_defconfig b/configs/P1023RDB_defconfig
index 3001575..1882eb8 100644
--- a/configs/P1023RDB_defconfig
+++ b/configs/P1023RDB_defconfig
@@ -7,6 +7,7 @@
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_OF_STDOUT_VIA_ALIAS=y
 CONFIG_BOOTDELAY=-1
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_I2C=y
 CONFIG_CMD_USB=y