mac80211: mesh path and mesh peer configuration

This adds code to allow adding mesh interfaces and configuring
mesh peers etc. Also, it adds code for station dumping.

Signed-off-by: Luis Carlos Cobo <luisca@cozybit.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>