ext4: Move fs/ext4/namei.h into ext4.h

The fs/ext4/namei.h header file had only a single function
declaration, and should have never been a standalone file.  Move it
into ext4.h, where should have been from the beginning.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index af3c906..d9c5251 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1594,6 +1594,7 @@
 /* namei.c */
 extern const struct inode_operations ext4_dir_inode_operations;
 extern const struct inode_operations ext4_special_inode_operations;
+extern struct dentry *ext4_get_parent(struct dentry *child);
 
 /* symlink.c */
 extern const struct inode_operations ext4_symlink_inode_operations;