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/comtrend_vr3032u_ram_defconfig b/configs/comtrend_vr3032u_ram_defconfig
index 2cb0bac..c557326 100644
--- a/configs/comtrend_vr3032u_ram_defconfig
+++ b/configs/comtrend_vr3032u_ram_defconfig
@@ -49,6 +49,7 @@
 CONFIG_MTD_RAW_NAND=y
 CONFIG_NAND_BRCMNAND=y
 CONFIG_NAND_BRCMNAND_6368=y
+CONFIG_SYS_NAND_ONFI_DETECTION=y
 CONFIG_DM_ETH=y
 CONFIG_BCM6368_ETH=y
 CONFIG_PHY=y