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/vinco_defconfig b/configs/vinco_defconfig
index 34a02bd..feed1dc 100644
--- a/configs/vinco_defconfig
+++ b/configs/vinco_defconfig
@@ -4,6 +4,7 @@
 CONFIG_SYS_EXTRA_OPTIONS="SAMA5D4,SYS_USE_SERIALFLASH"
 CONFIG_BOOTDELAY=3
 # CONFIG_DISPLAY_BOARDINFO is not set
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="vinco => "
 CONFIG_CMD_BOOTZ=y