PCI: Don't pass pci_dev to pci_ext_cfg_avail()

pci_ext_cfg_avail() doesn't use the "struct pci_dev *" passed to
it, and there's no requirement that a host bridge even be represented
by a pci_dev.  This drops the pci_ext_cfg_avail() parameter.

[bhelgaas: changelog]
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 7860942..9253af6 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1604,7 +1604,7 @@
 static inline void pci_mmcfg_late_init(void) { }
 #endif
 
-int pci_ext_cfg_avail(struct pci_dev *dev);
+int pci_ext_cfg_avail(void);
 
 void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar);