RDMA/cma: Delete useless kfree code

The parameter of kfree function is NULL, so kfree code is useless, delete
it.  Therefore, goto expression is no longer needed, so simplify
it. cma_dev_group is always pre-zero'd before reaching make_cma_ports, so
the NULL set to cma_dev_group->ports is unneeded too.

Link: https://lore.kernel.org/r/20201216080219.18184-1-zhengyongjun3@huawei.comSigned-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/core/cma_configfs.c

@@ -202,7 +202,6 @@ static int make_cma_ports(struct cma_dev_group *cma_dev_group,
 	unsigned int i;
 	unsigned int ports_num;
 	struct cma_dev_port_group *ports;
-	int err;
 
 	ibdev = cma_get_ib_dev(cma_dev);
 
@@ -213,10 +212,8 @@ static int make_cma_ports(struct cma_dev_group *cma_dev_group,
 	ports = kcalloc(ports_num, sizeof(*cma_dev_group->ports),
 			GFP_KERNEL);
 
-	if (!ports) {
-		err = -ENOMEM;
-		goto free;
-	}
+	if (!ports)
+		return -ENOMEM;
 
 	for (i = 0; i < ports_num; i++) {
 		char port_str[10];
@@ -232,12 +229,7 @@ static int make_cma_ports(struct cma_dev_group *cma_dev_group,
 
 	}
 	cma_dev_group->ports = ports;
-
 	return 0;
-free:
-	kfree(ports);
-	cma_dev_group->ports = NULL;
-	return err;
 }
 
 static void release_cma_dev(struct config_item  *item)