pci: provide prototype for pci_skip_dev outside of #if defined(CONFIG_DM_PCI_COMPAT)

The weak definition of pci_skip_dev from drivers/pci/pci_common.c is not
under CONFIG_DM_PCI_COMPAT, and that definition needs a previous
function prototype declaration to avoid W=1 build warnings.

That prototype is not available due to it being under CONFIG_DM_PCI_COMPAT,
so move it outside of that preprocessor block.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/pci.h b/include/pci.h
index 0fc22ad..11009a2 100644
--- a/include/pci.h
+++ b/include/pci.h
@@ -724,6 +724,7 @@
  */
 int pciauto_region_allocate(struct pci_region *res, pci_size_t size,
 			    pci_addr_t *bar, bool supports_64bit);
+int pci_skip_dev(struct pci_controller *hose, pci_dev_t dev);
 
 #if defined(CONFIG_DM_PCI_COMPAT)
 extern int pci_hose_read_config_byte_via_dword(struct pci_controller *hose,
@@ -741,7 +742,6 @@
 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);
 extern int pci_hose_scan_bus(struct pci_controller *hose, int bus);