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/colibri_t20_defconfig b/configs/colibri_t20_defconfig
index c9fb555..88ee270 100644
--- a/configs/colibri_t20_defconfig
+++ b/configs/colibri_t20_defconfig
@@ -48,6 +48,7 @@
 CONFIG_MTD=y
 CONFIG_DM_MTD=y
 CONFIG_MTD_RAW_NAND=y
+CONFIG_SYS_NAND_ONFI_DETECTION=y
 CONFIG_MTD_UBI_FASTMAP=y
 CONFIG_DM_PMIC=y
 CONFIG_DM_REGULATOR=y