ext4: fix build failure if DX_DEBUG is enabled

ext4_next_entry() is used by the debugging function dx_show_leaf(), so
it must be defined before that function.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/namei.c

@@ -182,6 +182,16 @@ static struct buffer_head * ext4_dx_find_entry(struct dentry *dentry,
 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
 			     struct inode *inode);
 
+/*
+ * p is at least 6 bytes before the end of page
+ */
+static inline struct ext4_dir_entry_2 *
+ext4_next_entry(struct ext4_dir_entry_2 *p)
+{
+	return (struct ext4_dir_entry_2 *)((char *)p +
+		ext4_rec_len_from_disk(p->rec_len));
+}
+
 /*
  * Future: use high four bits of block for coalesce-on-delete flags
  * Mask them off for now.
@@ -553,15 +563,6 @@ static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 }
 
 
-/*
- * p is at least 6 bytes before the end of page
- */
-static inline struct ext4_dir_entry_2 *ext4_next_entry(struct ext4_dir_entry_2 *p)
-{
-	return (struct ext4_dir_entry_2 *)((char *)p +
-		ext4_rec_len_from_disk(p->rec_len));
-}
-
 /*
  * This function fills a red-black tree with information from a
  * directory block.  It returns the number directory entries loaded