staging: erofs: don't check special inode layout

Currently, we will check if inode layout is compression or inline if
the inode is special in fill_inode(). Also set ->i_mapping->a_ops for
it. That is pointless since the both modes won't be set for special
inode when creating EROFS filesystem image. So, let's avoid it.
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/erofs/inode.c

@@ -204,6 +204,7 @@ static int fill_inode(struct inode *inode, int isdir)
 			S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 			inode->i_op = &erofs_generic_iops;
 			init_special_inode(inode, inode->i_mode, inode->i_rdev);
+			goto out_unlock;
 		} else {
 			err = -EIO;
 			goto out_unlock;