[SCSI] zfcp: Move workqueue to adapter struct

Remove the global driver work queue and replace it with a workqueue
local to the adapter. The usage of this workqueue makes this the
correct place for the structure. In addition multiple adapters won't
block each other due to the serialization of the queued work.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/s390/scsi/zfcp_erp.c

@@ -875,7 +875,7 @@ static int zfcp_erp_port_strategy_open_common(struct zfcp_erp_action *act)
 			return zfcp_erp_open_ptp_port(act);
 		if (!port->d_id) {
 			zfcp_port_get(port);
-			if (!queue_work(zfcp_data.work_queue,
+			if (!queue_work(adapter->work_queue,
 					&port->gid_pn_work))
 				zfcp_port_put(port);
 			return ZFCP_ERP_CONTINUES;