unregister_chrdev(): ignore the return value

unregister_chrdev() always returns 0.  There is no need to check the return
value.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/viotape.c b/drivers/char/viotape.c
index db57277..e12275d 100644
--- a/drivers/char/viotape.c
+++ b/drivers/char/viotape.c
@@ -1098,15 +1098,10 @@
 /* Cleanup */
 static void __exit viotap_exit(void)
 {
-	int ret;
-
 	remove_proc_entry("iSeries/viotape", NULL);
 	vio_unregister_driver(&viotape_driver);
 	class_destroy(tape_class);
-	ret = unregister_chrdev(VIOTAPE_MAJOR, "viotape");
-	if (ret < 0)
-		printk(VIOTAPE_KERN_WARN "Error unregistering device: %d\n",
-				ret);
+	unregister_chrdev(VIOTAPE_MAJOR, "viotape");
 	if (viotape_unitinfo)
 		dma_free_coherent(iSeries_vio_dev,
 				sizeof(viotape_unitinfo[0]) * VIOTAPE_MAX_TAPE,