net/smc: add missing dev_put

In the infiniband part, SMC currently uses get_netdev which calls
dev_hold on the returned net device. However, the SMC code never calls
dev_put on that net device resulting in a wrong reference count.

This patch adds a dev_put after the usage of the net device to fix the
issue.
Signed-off-by: Hans Wippel <hwippel@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_ib.c

@@ -380,6 +380,7 @@ static int smc_ib_fill_gid_and_mac(struct smc_ib_device *smcibdev, u8 ibport)
 	ndev = smcibdev->ibdev->get_netdev(smcibdev->ibdev, ibport);
 	if (ndev) {
 		memcpy(&smcibdev->mac, ndev->dev_addr, ETH_ALEN);
+		dev_put(ndev);
 	} else if (!rc) {
 		memcpy(&smcibdev->mac[ibport - 1][0],
 		       &smcibdev->gid[ibport - 1].raw[8], 3);