trivial: Documentation/rbtree.txt: cleanup kerneldoc of rbtree.txt

 The first formal parameter of the rb_link_node() is a pointer, and the
 "node" is define a data struct (pls see line 67 and line 73 in the
 doc), so the actual parameter should use "&data->node".
Signed-off-by: Figo.zhang <figo.zhang@kolorific.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Documentation/rbtree.txt

@@ -131,8 +131,8 @@ Example:
   	}
 
   	/* Add new node and rebalance tree. */
-  	rb_link_node(data->node, parent, new);
-  	rb_insert_color(data->node, root);
+  	rb_link_node(&data->node, parent, new);
+  	rb_insert_color(&data->node, root);
 
 	return TRUE;
   }
@@ -146,10 +146,10 @@ To remove an existing node from a tree, call:
 
 Example:
 
-  struct mytype *data = mysearch(mytree, "walrus");
+  struct mytype *data = mysearch(&mytree, "walrus");
 
   if (data) {
-  	rb_erase(data->node, mytree);
+  	rb_erase(&data->node, &mytree);
   	myfree(data);
   }