s390: remove WARN_ON for misc_deregister() failures

The previous change added WARN_ON() in misc_deregister().  So it is not
necessary to WARN_ON() misc_deregister() failure by callers.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/s390/block/dasd_eer.c

@@ -701,7 +701,7 @@ int __init dasd_eer_init(void)
 void dasd_eer_exit(void)
 {
 	if (dasd_eer_dev) {
-		WARN_ON(misc_deregister(dasd_eer_dev) != 0);
+		misc_deregister(dasd_eer_dev);
 		kfree(dasd_eer_dev);
 		dasd_eer_dev = NULL;
 	}

drivers/s390/char/monreader.c

@@ -627,7 +627,7 @@ static int __init mon_init(void)
 static void __exit mon_exit(void)
 {
 	segment_unload(mon_dcss_name);
-	WARN_ON(misc_deregister(&mon_dev) != 0);
+	misc_deregister(&mon_dev);
 	device_unregister(monreader_device);
 	driver_unregister(&monreader_driver);
 	iucv_unregister(&monreader_iucv_handler, 1);

drivers/s390/char/monwriter.c

@@ -380,7 +380,7 @@ static int __init mon_init(void)
 
 static void __exit mon_exit(void)
 {
-	WARN_ON(misc_deregister(&mon_dev) != 0);
+	misc_deregister(&mon_dev);
 	platform_device_unregister(monwriter_pdev);
 	platform_driver_unregister(&monwriter_pdrv);
 }