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/corvus_defconfig b/configs/corvus_defconfig
index fc10399..9ff228f 100644
--- a/configs/corvus_defconfig
+++ b/configs/corvus_defconfig
@@ -13,6 +13,7 @@
 CONFIG_SYS_EXTRA_OPTIONS="AT91SAM9M10G45,MACH_TYPE=2066,SYS_USE_NANDFLASH"
 CONFIG_BOOTDELAY=3
 # CONFIG_DISPLAY_BOARDINFO is not set
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SPL=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="U-Boot> "