pci: sorting out type confusion in pci_register_bar().

This patch sorts out invalid use of pcibus_t.

In pci_register_bar(), pcibus_t wmask is used.  It should,
however, be uint64_t because it is used to set
pci configuration space value(PCIDevice::wmask)
by pci_set_quad() or pci_set_long().
Signed-off-by: NIsaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/pci.c

@@ -763,7 +763,7 @@ void pci_register_bar(PCIDevice *pci_dev, int region_num,
 {
     PCIIORegion *r;
     uint32_t addr;
-    pcibus_t wmask;
+    uint64_t wmask;
 
     if ((unsigned int)region_num >= PCI_NUM_REGIONS)
         return;