net: gtp: Leverage core stats allocator

With commit 34d21de ("net: Move {l,t,d}stats allocation to core and
convert veth & vrf"), stats allocation could be done on net core
instead of in this driver.

With this new approach, the driver doesn't have to bother with error
handling (allocation failure checking, making sure free happens in the
right spot, etc). This is core responsibility now.

Remove the allocation in the gtp driver and leverage the network
core allocation instead.

Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Link: https://lore.kernel.org/r/20240305121524.2254533-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/gtp.c

@@ -717,10 +717,6 @@ static int gtp_dev_init(struct net_device *dev)
 
 	gtp->dev = dev;
 
-	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!dev->tstats)
-		return -ENOMEM;
-
 	return 0;
 }
 
@@ -729,7 +725,6 @@ static void gtp_dev_uninit(struct net_device *dev)
 	struct gtp_dev *gtp = netdev_priv(dev);
 
 	gtp_encap_disable(gtp);
-	free_percpu(dev->tstats);
 }
 
 static inline void gtp0_push_header(struct sk_buff *skb, struct pdp_ctx *pctx)
@@ -970,6 +965,7 @@ static void gtp_link_setup(struct net_device *dev)
 	dev->type = ARPHRD_NONE;
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	dev->priv_flags	|= IFF_NO_QUEUE;
 	dev->features	|= NETIF_F_LLTX;
 	netif_keep_dst(dev);