vfio-pci: Use PCI_MSIX_TABLE_BIR, not PCI_MSIX_FLAGS_BIRMASK

PCI_MSIX_FLAGS_BIRMASK is mis-named because the BIR mask is in the
Table Offset register, not the flags ("Message Control" per spec)
register.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/pci/vfio_pci.c

@@ -78,8 +78,8 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
 		pci_read_config_word(pdev, msix_pos + PCI_MSIX_FLAGS, &flags);
 		pci_read_config_dword(pdev, msix_pos + PCI_MSIX_TABLE, &table);
 
-		vdev->msix_bar = table & PCI_MSIX_FLAGS_BIRMASK;
-		vdev->msix_offset = table & ~PCI_MSIX_FLAGS_BIRMASK;
+		vdev->msix_bar = table & PCI_MSIX_TABLE_BIR;
+		vdev->msix_offset = table & PCI_MSIX_TABLE_OFFSET;
 		vdev->msix_size = ((flags & PCI_MSIX_FLAGS_QSIZE) + 1) * 16;
 	} else
 		vdev->msix_bar = 0xFF;