mac80211: set running state earlier

When an interface is brought up, the recent changes
to allow changing type-while-up only set the running
bit after everything was done. This broke a number
of things, including idle calculation for monitor
interfaces, and it also broke WDS station insertion
(although nobody noticed yet).

Thus, change the code to set the running bit earlier,
but keep it after the driver's add_interface was
called because otherwise drivers may iterate over
interfaces they haven't fully set up yet.

Reported-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>