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/bcm968380gerg_ram_defconfig b/configs/bcm968380gerg_ram_defconfig
index 855f1c2..7eb23bd 100644
--- a/configs/bcm968380gerg_ram_defconfig
+++ b/configs/bcm968380gerg_ram_defconfig
@@ -48,6 +48,7 @@
 CONFIG_MTD_RAW_NAND=y
 CONFIG_NAND_BRCMNAND=y
 CONFIG_NAND_BRCMNAND_6838=y
+CONFIG_SYS_NAND_ONFI_DETECTION=y
 CONFIG_PHY=y
 CONFIG_BCM6368_USBH_PHY=y
 CONFIG_PINCTRL=y