mac80211_hwsim: fix secondary MAC address assignment

OR'ing in 0x40 before a memcpy() to overwrite the value doesn't
do much good - flip the order of operations are reported and
tested by Jouni.

Fixes: cb1a5bae ("mac80211_hwsim: add permanent mac address option for new radios")
Reported-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>