net: introduce netdev_alloc_pcpu_stats() for drivers

There are many drivers calling alloc_percpu() to allocate pcpu stats
and then initializing ->syncp. So just introduce a helper function for them.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_device.c

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 63f0455..bf34451 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -88,18 +88,11 @@
 static int br_dev_init(struct net_device *dev)
 {
 	struct net_bridge *br = netdev_priv(dev);
-	int i;
 
-	br->stats = alloc_percpu(struct pcpu_sw_netstats);
+	br->stats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
 	if (!br->stats)
 		return -ENOMEM;
 
-	for_each_possible_cpu(i) {
-		struct pcpu_sw_netstats *br_dev_stats;
-		br_dev_stats = per_cpu_ptr(br->stats, i);
-		u64_stats_init(&br_dev_stats->syncp);
-	}
-
 	return 0;
 }