iwlwifi: use singlethread workqueue

Use one workqueue instead of one per CPU.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 87b237d..6e4dba1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -3370,7 +3370,7 @@
 
 static void iwl_setup_deferred_work(struct iwl_priv *priv)
 {
-	priv->workqueue = create_workqueue(DRV_NAME);
+	priv->workqueue = create_singlethread_workqueue(DRV_NAME);
 
 	init_waitqueue_head(&priv->wait_command_queue);