Convert CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT

In order to do this conversion, expose this option to the user and
use "save" not "safe" in the text.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/pm9g45_defconfig b/configs/pm9g45_defconfig
index 2d63a8c..7fbbbab 100644
--- a/configs/pm9g45_defconfig
+++ b/configs/pm9g45_defconfig
@@ -47,6 +47,7 @@
 CONFIG_AT91_GPIO=y
 CONFIG_GENERIC_ATMEL_MCI=y
 CONFIG_MTD=y
+CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT=y
 # CONFIG_SYS_NAND_USE_FLASH_BBT is not set
 CONFIG_NAND_ATMEL=y
 CONFIG_DM_ETH=y