[SCSI] zfcp: fix erp list usage without using locks

The zfcp_erp_thread was using the nolock version of the dbf function.
This resulted in a list access while other tasks could modifying the
list. The symptom was an erp thread running at 100% CPU and never
returning from the dbf function.
Signed-off-by: NSwen Schillig <swen@vnet.ibm.com>
Signed-off-by: NChristof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

drivers/s390/scsi/zfcp_erp.c

@@ -1395,9 +1395,9 @@ static int zfcp_erp_thread(void *data)
 				zfcp_erp_wakeup(adapter);
 		}
 
-		zfcp_rec_dbf_event_thread(4, adapter);
+		zfcp_rec_dbf_event_thread_lock(4, adapter);
 		down_interruptible(&adapter->erp_ready_sem);
-		zfcp_rec_dbf_event_thread(5, adapter);
+		zfcp_rec_dbf_event_thread_lock(5, adapter);
 	}
 
 	atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP, &adapter->status);