net: Use nlmsg_unicast() instead of netlink_unicast()

It has 'if (err >0 )' statement in nlmsg_unicast(), so use nlmsg_unicast()
instead of netlink_unicast(), this looks more concise.

v2: remove the change in netfilter.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/unix/diag.c b/net/unix/diag.c
index 9ff64f9..7e7d7f4 100644
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -295,10 +295,8 @@ static int unix_diag_get_exact(struct sk_buff *in_skb,
 
 		goto again;
 	}
-	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
-			      MSG_DONTWAIT);
-	if (err > 0)
-		err = 0;
+	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
+
 out:
 	if (sk)
 		sock_put(sk);