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/s32v234evb_defconfig b/configs/s32v234evb_defconfig
index 0da90dc..302ec6d 100644
--- a/configs/s32v234evb_defconfig
+++ b/configs/s32v234evb_defconfig
@@ -3,5 +3,6 @@
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_SYS_MALLOC_F=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/s32v234evb/s32v234evb.cfg"
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_CMD_BOOTZ=y
 CONFIG_OF_LIBFDT=y