[MAC80211]: implement cfg80211's change_interface hook

This implements the cfg80211 change_interface hook that changes the
type of an interface and cleans up the code a bit.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed