maple_tree: the return value of mas_root_expand() is not used

No user of the return value now, just remove it.

Link: https://lkml.kernel.org/r/20241031231627.14316-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: RichardWeiYang

lib/maple_tree.c

@@ -3408,7 +3408,7 @@ static noinline_for_kasan void mas_commit_b_node(struct ma_wr_state *wr_mas,
  * @mas: The maple state
  * @entry: The entry to store into the tree
  */
-static inline int mas_root_expand(struct ma_state *mas, void *entry)
+static inline void mas_root_expand(struct ma_state *mas, void *entry)
 {
 	void *contents = mas_root_locked(mas);
 	enum maple_type type = maple_leaf_64;
@@ -3444,7 +3444,7 @@ static inline int mas_root_expand(struct ma_state *mas, void *entry)
 	ma_set_meta(node, maple_leaf_64, 0, slot);
 	/* swap the new root into the tree */
 	rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
-	return slot;
+	return;
 }
 
 static inline void mas_store_root(struct ma_state *mas, void *entry)