mac80211_hwsim: support any address in userspace

Due to the checks in get_hwsim_data_ref_from_addr, wmediumd
was only able to use the second mac address (those starting with
0x42).  This is confusing and needlessly limiting, so allow any
configured address.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>