PCI: keystone: Prevent ARM32 specific code to be compiled for ARM64

[ Upstream commit f316a2b53cd7f37963ae20ec7072eb27a349a4ce ]

hook_fault_code() is an ARM32 specific API for hooking into data abort.

AM65X platforms (that integrate ARM v8 cores and select CONFIG_ARM64 as
arch) rely on pci-keystone.c but on them the enumeration of a
non-present BDF does not trigger a bus error, so the fixup exception
provided by calling hook_fault_code() is not needed and can be guarded
with CONFIG_ARM.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
[lorenzo.pieralisi@arm.com: commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/pci/controller/dwc/pci-keystone.c

@@ -237,6 +237,7 @@ static void ks_pcie_setup_interrupts(struct keystone_pcie *ks_pcie)
 		ks_dw_pcie_enable_error_irq(ks_pcie);
 }
 
+#ifdef CONFIG_ARM
 /*
  * When a PCI device does not exist during config cycles, keystone host gets a
  * bus error instead of returning 0xffffffff. This handler always returns 0
@@ -256,6 +257,7 @@ static int keystone_pcie_fault(unsigned long addr, unsigned int fsr,
 
 	return 0;
 }
+#endif
 
 static int __init ks_pcie_host_init(struct pcie_port *pp)
 {
@@ -279,12 +281,14 @@ static int __init ks_pcie_host_init(struct pcie_port *pp)
 	val |= BIT(12);
 	writel(val, pci->dbi_base + PCIE_CAP_BASE + PCI_EXP_DEVCTL);
 
+#ifdef CONFIG_ARM
 	/*
 	 * PCIe access errors that result into OCP errors are caught by ARM as
 	 * "External aborts"
 	 */
 	hook_fault_code(17, keystone_pcie_fault, SIGBUS, 0,
 			"Asynchronous external abort");
+#endif
 
 	return 0;
 }