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/sama5d2_ptc_ek_nandflash_defconfig b/configs/sama5d2_ptc_ek_nandflash_defconfig
index e7b48d6..9da97b3 100644
--- a/configs/sama5d2_ptc_ek_nandflash_defconfig
+++ b/configs/sama5d2_ptc_ek_nandflash_defconfig
@@ -58,6 +58,7 @@
 CONFIG_NAND_ATMEL=y
 CONFIG_ATMEL_NAND_HW_PMECC=y
 CONFIG_PMECC_CAP=4
+CONFIG_SYS_NAND_ONFI_DETECTION=y
 CONFIG_DM_ETH=y
 CONFIG_MACB=y
 CONFIG_PINCTRL=y