log: output hexdump of transmitted sccp messages

We output a hexdump for each sccp message we receive, but not when
sending.

Also log the hexdump of sccp messages when sending.

Change-Id: Ibfe52a0b7dbca4c569c603a008d73d0d99d1c345

src/osmo-bsc/osmo_bsc_sigtran.c

@@ -356,8 +356,8 @@ int osmo_bsc_sigtran_send(const struct osmo_bsc_sccp_con *conn, struct msgb *msg
 
 	ss7 = osmo_ss7_instance_find(msc->a.cs7_instance);
 	OSMO_ASSERT(ss7);
-	LOGP(DMSC, LOGL_DEBUG, "Sending connection (id=%i) oriented data to MSC: %si\n",
-	     conn_id, osmo_sccp_addr_name(ss7, &msc->a.msc_addr));
+	LOGP(DMSC, LOGL_DEBUG, "Sending connection (id=%i) oriented data to MSC: %s (%s)\n",
+	     conn_id, osmo_sccp_addr_name(ss7, &msc->a.msc_addr), osmo_hexdump(msg->data, msg->len));
 
 	rc = osmo_sccp_tx_data_msg(msc->a.sccp_user, conn_id, msg);