kernel: add missing symbol to generic

Signed-off-by: Jonas Gorski <[email protected]>

target/linux/generic/config-4.9

@@ -2611,6 +2611,7 @@ CONFIG_MTD_OF_PARTS=y
 # CONFIG_MTD_PHYSMAP is not set
 # CONFIG_MTD_PHYSMAP_COMPAT is not set
 CONFIG_MTD_PHYSMAP_OF=y
+# CONFIG_MTD_PHYSMAP_OF_VERSATILE is not set
 # CONFIG_MTD_PLATRAM is not set
 # CONFIG_MTD_PMC551 is not set
 # CONFIG_MTD_RAM is not set