zconfdump(), which is used for debugging, can't recognize P_SELECT,
P_RANGE and P_MENU (if associated with a symbol, aka "menuconfig"),
and output something like this:

config X86
  boolean
  default y
  unknown prop 6!
  unknown prop 6!
  unknown prop 6!
  ...
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>