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/tqma6s_wru4_mmc_defconfig b/configs/tqma6s_wru4_mmc_defconfig
index 2902c93..159ecd0 100644
--- a/configs/tqma6s_wru4_mmc_defconfig
+++ b/configs/tqma6s_wru4_mmc_defconfig
@@ -8,6 +8,7 @@
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_BOOTDELAY=3
 CONFIG_DEFAULT_FDT_FILE="imx6s-wru4.dtb"
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y
 CONFIG_AUTOBOOT_KEYED=y
 CONFIG_AUTOBOOT_PROMPT="Enter password in %d seconds to stop autoboot\n"