nl80211: Broadcast CMD_NEW_INTERFACE and CMD_DEL_INTERFACE

Let the other listeners being notified when a new or del interface
command has been issued, thus reducing later necessary request to be in
sync with current context.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>