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/seaboard_defconfig b/configs/seaboard_defconfig
index 7a32f36..f915b5b 100644
--- a/configs/seaboard_defconfig
+++ b/configs/seaboard_defconfig
@@ -35,6 +35,7 @@
 CONFIG_TEGRA_KEYBOARD=y
 CONFIG_MTD=y
 CONFIG_MTD_RAW_NAND=y
+CONFIG_SYS_NAND_ONFI_DETECTION=y
 CONFIG_DM_PMIC=y
 CONFIG_DM_REGULATOR=y
 CONFIG_DM_REGULATOR_FIXED=y