Drivers may need to track which vif is using VHT MU-MIMO.
Move the flag indicationg the ownership of MU_MIMO to
ieee80211_vif.
Signed-off-by: NSara Sharon <sara.sharon@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>