PCI: hv: Handle vmbus_sendpacket() failure in hv_compose_msi_msg()

Handle vmbus_sendpacket() failure in hv_compose_msi_msg().

I happened to find this when reading the code.  I didn't get a real issue
however.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: KY Srinivasan <kys@microsoft.com>
CC: Jake Oshins <jakeo@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>

drivers/pci/host/pci-hyperv.c

@@ -895,7 +895,9 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 			       sizeof(*int_pkt), (unsigned long)&ctxt.pkt,
 			       VM_PKT_DATA_INBAND,
 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
-	if (!ret)
+	if (ret)
+		goto free_int_desc;
+
 	wait_for_completion(&comp.comp_pkt.host_event);
 
 	if (comp.comp_pkt.completion_status < 0) {