[SCSI] zfcp: fix compile warning

Get rid of this one:

drivers/s390/scsi/zfcp_erp.c: In function 'zfcp_erp_thread':
drivers/s390/scsi/zfcp_erp.c:1400: warning: ignoring return value of
'down_interruptible', declared with attribute warn_unused_result

zfcp_erp_thread is a kernel thread which can't receive any signals.
So introduce a dummy variable and get rid of the warning.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/s390/scsi/zfcp_erp.c

@@ -1385,6 +1385,7 @@ static int zfcp_erp_thread(void *data)
 	struct list_head *next;
 	struct zfcp_erp_action *act;
 	unsigned long flags;
+	int ignore;
 
 	daemonize("zfcperp%s", dev_name(&adapter->ccw_device->dev));
 	/* Block all signals */
@@ -1407,7 +1408,7 @@ static int zfcp_erp_thread(void *data)
 		}
 
 		zfcp_rec_dbf_event_thread_lock(4, adapter);
-		down_interruptible(&adapter->erp_ready_sem);
+		ignore = down_interruptible(&adapter->erp_ready_sem);
 		zfcp_rec_dbf_event_thread_lock(5, adapter);
 	}