RDMA/mlx5: Remove NULL check before dev_{put, hold}

Coccinelle reports a warning

WARNING: NULL check before dev_{put, hold} functions is not needed

The reason is the call netdev_{put, hold} of dev_{put,hold} will check NULL
There is no need to check before using dev_{put, hold}

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Link: https://lore.kernel.org/r/ZjGC4qXrOwZE0aHi@octinomon.home
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: irenge

drivers/infiniband/hw/mlx5/main.c

@@ -264,8 +264,7 @@ static struct net_device *mlx5_ib_get_netdev(struct ib_device *device,
 	 */
 	read_lock(&ibdev->port[port_num - 1].roce.netdev_lock);
 	ndev = ibdev->port[port_num - 1].roce.netdev;
-	if (ndev)
-		dev_hold(ndev);
+	dev_hold(ndev);
 	read_unlock(&ibdev->port[port_num - 1].roce.netdev_lock);
 
 out: