mac80211: Accept broadcast probe responses on 6GHz band

An AP that operates on 6GHz may respond with a broadcast probe response.
Don't ignore such frames.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/20200131111300.891737-14-luca@coelho.fi


Signed-off-by: Johannes Berg <johannes.berg@intel.com>