Add support to mac80211 for changing the interface
type even when the interface is UP, if the driver
supports it.
To achieve this
* add a new driver callback for switching,
* split some of the interface up/down code out
into new functions (do_open/do_stop), and
* maintain an own __SDATA_RUNNING bit that will
not be set during interface type, so that any
other code doesn't use the interface.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>