IB/IWPM: Fix a potential skb leak

In case ibnl_put_msg fails in send_nlmsg_done,
the function returns with -ENOMEM without freeing.

This patch fixes this behavior.

Fixes: 30dc5e63 ("RDMA/core: Add support for iWARP Port Mapper user space service")
Signed-off-by: NMark Bloch <markb@mellanox.com>
Reviewed-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NLeon Romanovsky <leon@kernel.org>
Reviewed-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

drivers/infiniband/core/iwpm_util.c

@@ -634,6 +634,7 @@ static int send_nlmsg_done(struct sk_buff *skb, u8 nl_client, int iwpm_pid)
 	if (!(ibnl_put_msg(skb, &nlh, 0, 0, nl_client,
 			   RDMA_NL_IWPM_MAPINFO, NLM_F_MULTI))) {
 		pr_warn("%s Unable to put NLMSG_DONE\n", __func__);
+		dev_kfree_skb(skb);
 		return -ENOMEM;
 	}
 	nlh->nlmsg_type = NLMSG_DONE;