RDMA/rw: use DIV_ROUND_UP to calculate nr_ops

Don't open-code DIV_ROUND_UP() kernel macro.

Link: https://lore.kernel.org/r/20200413133905.933343-1-leon@kernel.orgSigned-off-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/rw.c

@@ -129,7 +129,7 @@ static int rdma_rw_init_mr_wrs(struct rdma_rw_ctx *ctx, struct ib_qp *qp,
 						    qp->integrity_en);
 	int i, j, ret = 0, count = 0;
 
-	ctx->nr_ops = (sg_cnt + pages_per_mr - 1) / pages_per_mr;
+	ctx->nr_ops = DIV_ROUND_UP(sg_cnt, pages_per_mr);
 	ctx->reg = kcalloc(ctx->nr_ops, sizeof(*ctx->reg), GFP_KERNEL);
 	if (!ctx->reg) {
 		ret = -ENOMEM;