Revert "virtio_pci: don't duplicate the msix_enable flag in struct pci_dev"

This reverts commit 53a020c661741f3b87ad3ac6fa545088aaebac9b.

The cleanup seems to be one of the changes that broke
hybernation for some users. We are still not sure why
but revert helps.

Tested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index 15b4385..90007a1 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -79,7 +79,7 @@
  * configuration space */
 #define VIRTIO_PCI_CONFIG_OFF(msix_enabled)	((msix_enabled) ? 24 : 20)
 /* Deprecated: please use VIRTIO_PCI_CONFIG_OFF instead */
-#define VIRTIO_PCI_CONFIG(dev)	VIRTIO_PCI_CONFIG_OFF((dev)->pci_dev->msix_enabled)
+#define VIRTIO_PCI_CONFIG(dev)	VIRTIO_PCI_CONFIG_OFF((dev)->msix_enabled)
 
 /* Virtio ABI version, this must match exactly */
 #define VIRTIO_PCI_ABI_VERSION		0