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/malta64el_defconfig b/configs/malta64el_defconfig
index b3b1401..cd8dc14 100644
--- a/configs/malta64el_defconfig
+++ b/configs/malta64el_defconfig
@@ -3,6 +3,7 @@
 CONFIG_SYS_LITTLE_ENDIAN=y
 CONFIG_CPU_MIPS64_R2=y
 CONFIG_DEFAULT_DEVICE_TREE="mti,malta"
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="maltael # "
 # CONFIG_AUTOBOOT is not set