RDMA/cma: Fix error flow in default_roce_mode_store

In default_roce_mode_store(), we took a reference to cma_dev, but didn't
return it with cma_dev_put in the error flow.

Fixes: 1c15b4f2a4 ("RDMA/core: Modify enum ib_gid_type and enum rdma_network_type")
Link: https://lore.kernel.org/r/20210113130214.562108-1-leon@kernel.org
Signed-off-by: Neta Ostrovsky <netao@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/core/cma_configfs.c

@@ -131,8 +131,10 @@ static ssize_t default_roce_mode_store(struct config_item *item,
 		return ret;
 
 	gid_type = ib_cache_gid_parse_type_str(buf);
-	if (gid_type < 0)
+	if (gid_type < 0) {
+		cma_configfs_params_put(cma_dev);
 		return -EINVAL;
+	}
 
 	ret = cma_set_default_gid_type(cma_dev, group->port_num, gid_type);