ralink: add missing CONFIG_ symbol to mt7620n

Signed-off-by: John Crispin <blogic@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38867 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/ramips/mt7620n/config-3.10

@@ -96,6 +96,7 @@ CONFIG_MODULES_USE_ELF_REL=y
 # CONFIG_MTD_CFI_INTELEXT is not set
 CONFIG_MTD_CMDLINE_PARTS=y
 CONFIG_MTD_M25P80=y
+# CONFIG_MTD_NAND_MT7620 is not set
 CONFIG_MTD_OF_PARTS=y
 CONFIG_MTD_PHYSMAP=y
 CONFIG_MTD_PHYSMAP_OF=y