packet: propagate sock_cmsg_send() error

sock_cmsg_send() can return different error codes and not only
-EINVAL, and we should properly propagate them.

Fixes: c14ac9451c34 ("sock: enable timestamping using control messages")
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -1930,10 +1930,8 @@ retry:
 	sockc.tsflags = sk->sk_tsflags;
 	if (msg->msg_controllen) {
 		err = sock_cmsg_send(sk, msg, &sockc);
-		if (unlikely(err)) {
-			err = -EINVAL;
+		if (unlikely(err))
 			goto out_unlock;
-		}
 	}
 
 	skb->protocol = proto;