net: treewide use of RCU_INIT_POINTER

rcu_assign_pointer(ptr, NULL) can be safely replaced by
RCU_INIT_POINTER(ptr, NULL)

(old rcu_assign_pointer() macro was testing the NULL value and could
omit the smp_wmb(), but this had to be removed because of compiler
warnings)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ppp/pptp.c b/drivers/net/ppp/pptp.c
index 89f829f..ede899c 100644
--- a/drivers/net/ppp/pptp.c
+++ b/drivers/net/ppp/pptp.c
@@ -162,7 +162,7 @@
 {
 	spin_lock(&chan_lock);
 	clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
-	rcu_assign_pointer(callid_sock[sock->proto.pptp.src_addr.call_id], NULL);
+	RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL);
 	spin_unlock(&chan_lock);
 	synchronize_rcu();
 }