PCI: dwc: Make hisi_pcie_platform_ops static

Fix the following sparse warning:

drivers/pci/controller/dwc/pcie-hisi.c:365:21: warning:
symbol 'hisi_pcie_platform_ops' was not declared. Should it be static?

Link: https://lore.kernel.org/r/1587611883-26960-1-git-send-email-zou_wei@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Zhou Wang <wangzhou1@hisilicon.com>

drivers/pci/controller/dwc/pcie-hisi.c

@@ -362,7 +362,7 @@ static int hisi_pcie_platform_init(struct pci_config_window *cfg)
 	return 0;
 }
 
-struct pci_ecam_ops hisi_pcie_platform_ops = {
+static struct pci_ecam_ops hisi_pcie_platform_ops = {
 	.bus_shift    = 20,
 	.init         =  hisi_pcie_platform_init,
 	.pci_ops      = {