wifi: nl80211: Update the documentation of NL80211_SCAN_FLAG_COLOCATED_6GHZ

Add a detailed description of NL80211_SCAN_FLAG_COLOCATED_6GHZ
flag.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230301115906.487ab04feb39.I5129fd61841332474693046241586f057b134c3c@changeid


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