nilfs2: nilfs_iget_for_gc() returns ERR_PTR

nilfs_iget_for_gc() returns an ERR_PTR() on failure and doesn't return
NULL.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

fs/nilfs2/ioctl.c

@@ -349,8 +349,8 @@ static int nilfs_ioctl_move_blocks(struct super_block *sb,
 		ino = vdesc->vd_ino;
 		cno = vdesc->vd_cno;
 		inode = nilfs_iget_for_gc(sb, ino, cno);
-		if (unlikely(inode == NULL)) {
-			ret = -ENOMEM;
+		if (IS_ERR(inode)) {
+			ret = PTR_ERR(inode);
 			goto failed;
 		}
 		do {