Convert CONFIG_USE_ONENAND_BOARD_INIT to Kconfig

This converts the following to Kconfig:
   CONFIG_USE_ONENAND_BOARD_INIT

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/igep00x0_defconfig b/configs/igep00x0_defconfig
index 00f0a67..17c97ac 100644
--- a/configs/igep00x0_defconfig
+++ b/configs/igep00x0_defconfig
@@ -52,6 +52,7 @@
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_NAND=y
 CONFIG_CMD_ONENAND=y
+CONFIG_USE_ONENAND_BOARD_INIT=y
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_MTDPARTS=y