wlcore: clear roc_vif on iface removal

When removing an interface currently performing a ROC operation, clear
the current ROC state. This is useful especially during recovery and
keeps mac80211 in sync to our state.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>