nl80211: ensure interface is up in various APIs

nl80211: ensure interface is up in various APIs

commit 2b5f8b0b44e17e625cfba1e7b88db44f4dcc0441 upstream.
[backported by Ben Greear]

The nl80211 handling code should ensure as much as
it can that the interface is in a valid state, it
can certainly ensure the interface is running.

Not doing so can cause calls through mac80211 into
the driver that result in warnings and unspecified
behaviour in the driver.

Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>