dm: return earlier from dm_blk_ioctl if target doesn't implement .ioctl

No point checking if the device is suspended if the current target
doesn't even implement .ioctl
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm.c

@@ -525,13 +525,14 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
 		goto out;
 
 	tgt = dm_table_get_target(map, 0);
+	if (!tgt->type->ioctl)
+		goto out;
 
 	if (dm_suspended_md(md)) {
 		r = -EAGAIN;
 		goto out;
 	}
 
-	if (tgt->type->ioctl)
 	r = tgt->type->ioctl(tgt, cmd, arg);
 
 out: