PCI: spear13xx: Avoid invalid address space conversions

The sparse checker complains about converting pointers between address
spaces.  We correctly stored an __iomem pointer in struct spear13xx_pcie,
but discarded the __iomem when extracting app_base, causing one warning.
Then we passed the non-__iomem pointer to writel(), which expects an
__iomem pointer, causing another warning.

Add the appropriate annotations.

The sparse warnings look like this:

  $ make C=2 drivers/pci/controller/
  drivers/pci/controller/dwc/pcie-spear13xx.c:72:54: warning: incorrect type in initializer (different address spaces)
  drivers/pci/controller/dwc/pcie-spear13xx.c:72:54:    expected struct pcie_app_reg *app_reg
  drivers/pci/controller/dwc/pcie-spear13xx.c:72:54:    got void [noderef] __iomem *app_base
  drivers/pci/controller/dwc/pcie-spear13xx.c:78:26: warning: incorrect type in argument 2 (different address spaces)
  drivers/pci/controller/dwc/pcie-spear13xx.c:78:26:    expected void volatile [noderef] __iomem *addr
  drivers/pci/controller/dwc/pcie-spear13xx.c:78:26:    got unsigned int *

Link: https://lore.kernel.org/r/20211223213749.1314142-3-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Pratyush Anand <pratyush.anand@gmail.com>

drivers/pci/controller/dwc/pcie-spear13xx.c

@@ -69,7 +69,7 @@ struct pcie_app_reg {
 static int spear13xx_pcie_start_link(struct dw_pcie *pci)
 {
 	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pci);
-	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
+	struct pcie_app_reg __iomem *app_reg = spear13xx_pcie->app_base;
 
 	/* enable ltssm */
 	writel(DEVICE_TYPE_RC | (1 << MISCTRL_EN_ID)
@@ -83,7 +83,7 @@ static int spear13xx_pcie_start_link(struct dw_pcie *pci)
 static irqreturn_t spear13xx_pcie_irq_handler(int irq, void *arg)
 {
 	struct spear13xx_pcie *spear13xx_pcie = arg;
-	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
+	struct pcie_app_reg __iomem *app_reg = spear13xx_pcie->app_base;
 	struct dw_pcie *pci = spear13xx_pcie->pci;
 	struct pcie_port *pp = &pci->pp;
 	unsigned int status;
@@ -102,7 +102,7 @@ static irqreturn_t spear13xx_pcie_irq_handler(int irq, void *arg)
 
 static void spear13xx_pcie_enable_interrupts(struct spear13xx_pcie *spear13xx_pcie)
 {
-	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
+	struct pcie_app_reg __iomem *app_reg = spear13xx_pcie->app_base;
 
 	/* Enable MSI interrupt */
 	if (IS_ENABLED(CONFIG_PCI_MSI))
@@ -113,7 +113,7 @@ static void spear13xx_pcie_enable_interrupts(struct spear13xx_pcie *spear13xx_pc
 static int spear13xx_pcie_link_up(struct dw_pcie *pci)
 {
 	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pci);
-	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
+	struct pcie_app_reg __iomem *app_reg = spear13xx_pcie->app_base;
 
 	if (readl(&app_reg->app_status_1) & XMLH_LINK_UP)
 		return 1;