PCI: hv: Handle hv_pci_generic_compl() error case

'completion_status' is used in some places, e.g.,
hv_pci_protocol_negotiation(), so we should make sure it's initialized in
error case too, though the error is unlikely here.

[bhelgaas: fix changelog typo and nearby whitespace]
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

@@ -447,15 +447,16 @@ struct hv_pci_compl {
  * for any message for which the completion packet contains a
  * status and nothing else.
  */
-static
-void
-hv_pci_generic_compl(void *context, struct pci_response *resp,
+static void hv_pci_generic_compl(void *context, struct pci_response *resp,
 				 int resp_packet_size)
 {
 	struct hv_pci_compl *comp_pkt = context;
 
 	if (resp_packet_size >= offsetofend(struct pci_response, status))
 		comp_pkt->completion_status = resp->status;
+	else
+		comp_pkt->completion_status = -1;
+
 	complete(&comp_pkt->host_event);
 }