pci: make pci_get_hose_head() available to external users

Put pci_get_hose_head() prototype in header so it is available to
external users, allowing them to find and iterate over all pci
controllers.

Signed-off-by: Stuart Yoder <stuart.yoder@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>

include/pci.h

@@ -700,6 +700,7 @@ extern void *pci_map_bar(pci_dev_t pdev, int bar, int flags);
 extern void pci_register_hose(struct pci_controller* hose);
 extern struct pci_controller* pci_bus_to_hose(int bus);
 extern struct pci_controller *find_hose_by_cfg_addr(void *cfg_addr);
+extern struct pci_controller *pci_get_hose_head(void);
 
 extern int pci_skip_dev(struct pci_controller *hose, pci_dev_t dev);
 extern int pci_hose_scan(struct pci_controller *hose);