Convert CONFIG_SYS_NAND_ONFI_DETECTION to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_NAND_ONFI_DETECTION

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/vf610twr_defconfig b/configs/vf610twr_defconfig
index add1a07..0a7b663 100644
--- a/configs/vf610twr_defconfig
+++ b/configs/vf610twr_defconfig
@@ -46,6 +46,7 @@
 CONFIG_FSL_ESDHC_IMX=y
 CONFIG_MTD=y
 CONFIG_NAND_VF610_NFC=y
+CONFIG_SYS_NAND_ONFI_DETECTION=y
 CONFIG_SYS_NAND_BUSWIDTH_16BIT=y
 CONFIG_PHYLIB=y
 CONFIG_PHY_MICREL=y