Revert "mac80211_hwsim: support any address in userspace"

This reverts commit cd37a90b.

Different userspace programs interpreted HWSIM_ATTR_ADDR_TRANSMITTER
and HWSIM_ATTR_ADDR_RECEIVER differently: some expected it to
be an unchanging hardware address that is tied to the radio despite
which address is configured on the interface, while others expected
to be a copy of the address in the frame (the configured address).
The intent of the original authors is unclear.

The latter interpretation doesn't really work properly with multiple
vifs and broadcast frames.  Also, as the TA is already in the
frame, userspace programs can actually support configured addresses
in the former interpretation by mapping between them and the supplied
HWSIM_ATTR_ADDR_TRANSMITTER.

So, in the interest of API stability, revert to the previous mode
of operation and going forward use the former interpretation.

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