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/P1010RDB-PB_36BIT_SPIFLASH_defconfig b/configs/P1010RDB-PB_36BIT_SPIFLASH_defconfig
index 2d356ae..a5c3d74 100644
--- a/configs/P1010RDB-PB_36BIT_SPIFLASH_defconfig
+++ b/configs/P1010RDB-PB_36BIT_SPIFLASH_defconfig
@@ -17,6 +17,7 @@
 CONFIG_SYS_EXTRA_OPTIONS="SPIFLASH"
 CONFIG_BOOTDELAY=10
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
+CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SPL=y
 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT=y
 CONFIG_HUSH_PARSER=y