BUG_ON cleanup for drivers/md/

This changes two if() BUG(); usages to BUG_ON(); so people
can disable it safely.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

drivers/md/md.c

@@ -4438,8 +4438,7 @@ static int md_release(struct inode *inode, struct file * file)
 {
  	mddev_t *mddev = inode->i_bdev->bd_disk->private_data;
 
-	if (!mddev)
-		BUG();
+	BUG_ON(!mddev);
 	mddev_put(mddev);
 
 	return 0;

drivers/md/raid5.c

@@ -1105,7 +1105,7 @@ static void compute_parity6(struct stripe_head *sh, int method)
 				if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
 					wake_up(&conf->wait_for_overlap);
 
-				if (sh->dev[i].written) BUG();
+				BUG_ON(sh->dev[i].written);
 				sh->dev[i].written = chosen;
 			}
 		break;