maple_tree: change mas_adopt_children() parent usage

All calls to mas_adopt_children() currently pass the parent as the node in
the maple state.  Allow for the parent pointer that is passed in to be
used instead.

Link: https://lkml.kernel.org/r/20230804165951.2661157-6-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/maple_tree.c

@@ -1702,7 +1702,7 @@ static inline void mas_adopt_children(struct ma_state *mas,
 		struct maple_enode *parent)
 {
 	enum maple_type type = mte_node_type(parent);
-	struct maple_node *node = mas_mn(mas);
+	struct maple_node *node = mte_to_node(parent);
 	void __rcu **slots = ma_slots(node, type);
 	unsigned long *pivots = ma_pivots(node, type);
 	struct maple_enode *child;