pci: pci_write_config can be static

To avoid W=1 build warnings, declare this function as static, since it
is not used outside of this translation module.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

drivers/pci/pci-uclass.c

@@ -304,8 +304,8 @@ int pci_bus_clrset_config32(struct udevice *bus, pci_dev_t bdf, int offset,
 	return pci_bus_write_config(bus, bdf, offset, val, PCI_SIZE_32);
 }
 
-int pci_write_config(pci_dev_t bdf, int offset, unsigned long value,
-		     enum pci_size_t size)
+static int pci_write_config(pci_dev_t bdf, int offset, unsigned long value,
+			    enum pci_size_t size)
 {
 	struct udevice *bus;
 	int ret;