IB/hfi1: Fix tstats alloc and dealloc

The tstats allocation is done in the accelerated ndo_init function but the
allocation is not tested to succeed.

The deallocation is not done in the accelerated ndo_uninit function.

Resolve issues by testing for an allocation failure and adding the
free_percpu in the uninit function.

Fixes: aa0616a9bd52 ("IB/hfi1: switch to core handling of rx/tx byte/packet counters")
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Dennis Dalessandro <[e-mail]>
Signed-off-by: Mike Marciniszyn <[e-mail]>
Signed-off-by: Jason Gunthorpe <[e-mail]>

drivers/infiniband/hw/hfi1/ipoib_main.c

···
 	int ret;
 
 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
+	if (!dev->tstats)
+		return -ENOMEM;
 
 	ret = priv->netdev_ops->ndo_init(dev);
 	if (ret)
-		return ret;
+		goto out_ret;
 
 	ret = hfi1_netdev_add_data(priv->dd,
 				   qpn_from_mac(priv->netdev->dev_addr),
 				   dev);
 	if (ret < 0) {
 		priv->netdev_ops->ndo_uninit(dev);
-		return ret;
+		goto out_ret;
 	}
 
 	return 0;
+out_ret:
+	free_percpu(dev->tstats);
+	dev->tstats = NULL;
+	return ret;
 }
 
 static void hfi1_ipoib_dev_uninit(struct net_device *dev)
 {
 	struct hfi1_ipoib_dev_priv *priv = hfi1_ipoib_priv(dev);
+
+	free_percpu(dev->tstats);
+	dev->tstats = NULL;
 
 	hfi1_netdev_remove_data(priv->dd, qpn_from_mac(priv->netdev->dev_addr));
 
···
 	hfi1_ipoib_rxq_deinit(priv->netdev);
 
 	free_percpu(dev->tstats);
+	dev->tstats = NULL;
 }
 
 static void hfi1_ipoib_set_id(struct net_device *dev, int id)