All other code paths in sta_unblock synchronize with the network
softirq by using local_bh_disable/enable. Do the same around
ieee80211_sta_ps_deliver_wakeup.
Signed-off-by: NHelmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>