mctp-demux-daemon: Warn about failed messages

It's possible that messages might not be sent if they are routed to a
binding before that binding has completed its protocol initialisation.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I1ddf6817fdef974b61dcb3ce0f166af94b4b0f16
diff --git a/utils/mctp-demux-daemon.c b/utils/mctp-demux-daemon.c
index fc5d583..0774350 100644
--- a/utils/mctp-demux-daemon.c
+++ b/utils/mctp-demux-daemon.c
@@ -60,7 +60,11 @@
 
 static void tx_message(struct ctx *ctx, mctp_eid_t eid, void *msg, size_t len)
 {
-	mctp_message_tx(ctx->mctp, eid, msg, len);
+	int rc;
+
+	rc = mctp_message_tx(ctx->mctp, eid, msg, len);
+	if (rc)
+		warnx("Failed to send message: %d", rc);
 }
 
 static void client_remove_inactive(struct ctx *ctx)