ipv6: rename datagram_send_ctl and datagram_recv_ctl

The datagram_*_ctl functions in net/ipv6/datagram.c are IPv6-specific.  Since
datagram_send_ctl is publicly exported it should be appropriately named to
reflect the fact that it's for IPv6 only.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index 29124b7..d6de4b4 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -365,8 +365,8 @@
 		msg.msg_control = (void*)(fl->opt+1);
 		memset(&flowi6, 0, sizeof(flowi6));
 
-		err = datagram_send_ctl(net, sk, &msg, &flowi6, fl->opt, &junk,
-					&junk, &junk);
+		err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, fl->opt,
+					    &junk, &junk, &junk);
 		if (err)
 			goto done;
 		err = -EINVAL;