iwlwifi: allow probe-after-rx on 2.4 GHz

There are two passive 2.4 GHz channels: 12 and 13.
If you have a hidden SSID on those, you will not
be able to connect to it because we don't send out
probe requests there. We can allow this by using
the firmware's probe-after-rx functionality on
those channels as well.

This fixes
https://bugzilla.kernel.org/show_bug.cgi?id=16462



Reported-by: Daniel J Blueman <daniel.blueman@gmail.com>
Tested-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>