block: always set bdev->bd_part

Till now, bdev->bd_part is set only if the bdev was for parts other
than part0.  This patch makes bdev->bd_part always set so that code
paths don't have to differenciate common handling.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 96e9fcc..2bd9cf4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1464,10 +1464,7 @@
 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
 		goto fail;
 
-	if (rdev->bdev->bd_part)
-		ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
-	else
-		ko = &disk_to_dev(rdev->bdev->bd_disk)->kobj;
+	ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
 	if ((err = sysfs_create_link(&rdev->kobj, ko, "block"))) {
 		kobject_del(&rdev->kobj);
 		goto fail;