net: ethernet: Use DIV_ROUND_UP instead of reimplementing its function

DIV_ROUND_UP has implemented the code-opened function. Therefore, just
replace the implementation with DIV_ROUND_UP.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Acked-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/mellanox/mlx4/alloc.c b/drivers/net/ethernet/mellanox/mlx4/alloc.c
index 4bdf250..deef5a9 100644
--- a/drivers/net/ethernet/mellanox/mlx4/alloc.c
+++ b/drivers/net/ethernet/mellanox/mlx4/alloc.c
@@ -614,7 +614,7 @@ int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
 		int i;
 
 		buf->direct.buf = NULL;
-		buf->nbufs	= (size + PAGE_SIZE - 1) / PAGE_SIZE;
+		buf->nbufs      = DIV_ROUND_UP(size, PAGE_SIZE);
 		buf->npages	= buf->nbufs;
 		buf->page_shift  = PAGE_SHIFT;
 		buf->page_list   = kcalloc(buf->nbufs, sizeof(*buf->page_list),