maple_tree: use correct variable type in sizeof

The type of variable pointed to by pivs is unsigned long, but the type
used in sizeof is a pointer type.  Change it to unsigned long.

This change has no runtime effect, as sizeof(ul) == sizeof(ul *).

Link: https://lkml.kernel.org/r/20230411023513.15227-1-zhangpeng.00@bytedance.com
Fixes: 54a611b6 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reported-by: David Binderman <dcb314@hotmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/maple_tree.c

@@ -3258,7 +3258,7 @@ static inline void mas_destroy_rebalance(struct ma_state *mas, unsigned char end
 
 		if (tmp < max_p)
 			memset(pivs + tmp, 0,
-			       sizeof(unsigned long *) * (max_p - tmp));
+			       sizeof(unsigned long) * (max_p - tmp));
 
 		if (tmp < mt_slots[mt])
 			memset(slots + tmp, 0, sizeof(void *) * (max_s - tmp));