netpoll: use DEFINE_STATIC_SRCU() to define netpoll_srcu

DEFINE_STATIC_SRCU() defines srcu struct and do init at build time.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/netpoll.c

@@ -47,7 +47,7 @@ static struct sk_buff_head skb_pool;
 
 static atomic_t trapped;
 
-static struct srcu_struct netpoll_srcu;
+DEFINE_STATIC_SRCU(netpoll_srcu);
 
 #define USEC_PER_POLL	50
 #define NETPOLL_RX_ENABLED  1
@@ -1212,7 +1212,6 @@ EXPORT_SYMBOL(netpoll_setup);
 static int __init netpoll_init(void)
 {
 	skb_queue_head_init(&skb_pool);
-	init_srcu_struct(&netpoll_srcu);
 	return 0;
 }
 core_initcall(netpoll_init);