net: move and rename netif_notify_peers()

I believe net/core/dev.c is a better place for netif_notify_peers(),
because other net event notify functions also stay in this file.

And rename it to netdev_notify_peers().

Cc: David S. Miller <davem@davemloft.net>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 3089990..39afd37 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1731,7 +1731,7 @@
 		break;
 
 	case XenbusStateConnected:
-		netif_notify_peers(netdev);
+		netdev_notify_peers(netdev);
 		break;
 
 	case XenbusStateClosing: