saner calling conventions for copy_mount_options()

let it just return NULL, pointer to kernel copy or ERR_PTR().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/internal.h

@@ -55,7 +55,7 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 /*
  * namespace.c
  */
-extern int copy_mount_options(const void __user *, unsigned long *);
+extern void *copy_mount_options(const void __user *);
 extern char *copy_mount_string(const void __user *);
 
 extern struct vfsmount *lookup_mnt(struct path *);