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>
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index f418f4f..12c6a66 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2784,7 +2784,6 @@
 	const char *mac_from;
 	int phy_mode;
 	int err;
-	int cpu;
 
 	/* Our multiqueue support is not complete, so for now, only
 	 * allow the usage of the first RX queue
@@ -2845,18 +2844,12 @@
 	}
 
 	/* Alloc per-cpu stats */
-	pp->stats = alloc_percpu(struct mvneta_pcpu_stats);
+	pp->stats = netdev_alloc_pcpu_stats(struct mvneta_pcpu_stats);
 	if (!pp->stats) {
 		err = -ENOMEM;
 		goto err_unmap;
 	}
 
-	for_each_possible_cpu(cpu) {
-		struct mvneta_pcpu_stats *stats;
-		stats = per_cpu_ptr(pp->stats, cpu);
-		u64_stats_init(&stats->syncp);
-	}
-
 	dt_mac_addr = of_get_mac_address(dn);
 	if (dt_mac_addr) {
 		mac_from = "device tree";