mptcp: avoid unneeded address copy

In the syn_recv fallback path, the msk is unused. We can skip
setting the socket address.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/subflow.c

@@ -821,8 +821,6 @@ create_child:
 				goto dispose_child;
 			}
 
-			if (new_msk)
-				mptcp_copy_inaddrs(new_msk, child);
 			mptcp_subflow_drop_ctx(child);
 			goto out;
 		}