These frames are used for verifying that a specific SA and protected
link is in functional state between two devices. The IEEE 802.11
standard defines only a case that uses individual MAC address as the
destination. While there is no explicit rule on the receiver to ignore
other cases, it seems safer to make sure group-addressed frames do not
end up resulting in undesired behavior. As such, drop such frames
instead of interpreting them as valid SA Query Request/Response.