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/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index a4073b9..e8528cb 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -10,9 +10,9 @@
 	  NAND initialization process.
 
 config SYS_NAND_DRIVER_ECC_LAYOUT
-	bool
+	bool "Omit standard ECC layouts to save space"
 	help
-	  Omit standard ECC layouts to safe space. Select this if your driver
+	  Omit standard ECC layouts to save space. Select this if your driver
 	  is known to provide its own ECC layout.
 
 config SYS_NAND_USE_FLASH_BBT