PCI: Switch msix_program_entries() to use pci_msix_desc_addr()

Instead of relying on the msix_entry structure for the vector number, read
it from the msi_desc.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alexander Gordeev <agordeev@redhat.com>
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 0d94fbf..a385f39 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -713,11 +713,9 @@
 	int i = 0;
 
 	for_each_pci_msi_entry(entry, dev) {
-		int offset = entries[i].entry * PCI_MSIX_ENTRY_SIZE +
-						PCI_MSIX_ENTRY_VECTOR_CTRL;
-
 		entries[i].vector = entry->irq;
-		entry->masked = readl(entry->mask_base + offset);
+		entry->masked = readl(pci_msix_desc_addr(entry) +
+				PCI_MSIX_ENTRY_VECTOR_CTRL);
 		msix_mask_irq(entry, 1);
 		i++;
 	}