Convert CONFIG_SYS_NAND_HW_ECC to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_NAND_HW_ECC

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index 49b7a4b..0e42841 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -148,9 +148,21 @@
 	  Enable this driver for NAND flash controllers available in TI Davinci
 	  and Keystone2 platforms
 
+choice
+	prompt "Type of ECC used on NAND"
+	default SYS_NAND_4BIT_HW_ECC_OOBFIRST
+	depends on NAND_DAVINCI
+
+config SYS_NAND_HW_ECC
+	bool "Use 1-bit HW ECC"
+
 config SYS_NAND_4BIT_HW_ECC_OOBFIRST
 	bool "Use 4-bit HW ECC with OOB at the front"
-	depends on NAND_DAVINCI
+
+config SYS_NAND_SOFT_ECC
+	bool "Use software ECC"
+
+endchoice
 
 config KEYSTONE_RBL_NAND
 	depends on ARCH_KEYSTONE