mac80211: wait for scan work complete before restarting hw

This is needed to avoid warning in ieee80211_restart_hw about hardware
scan in progress.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi W Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index a06b6ee..7fb1148 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -305,6 +305,9 @@
 
 	trace_api_restart_hw(local);
 
+	/* wait for scan work complete */
+	flush_workqueue(local->workqueue);
+
 	WARN(test_bit(SCAN_HW_SCANNING, &local->scanning),
 		"%s called with hardware scan in progress\n", __func__);