x86: Move pci init function to x86_init

The PCI initialization in pci_subsys_init() is a mess. pci_numaq_init,
pci_acpi_init, pci_visws_init and pci_legacy_init are called and each
implementation checks and eventually modifies the global variable
pcibios_scanned.

x86_init functions allow us to do this more elegant. The pci.init
function pointer is preset to pci_legacy_init. numaq, acpi and visws
can modify the pointer in their early setup functions. The functions
return 0 when they did the full initialization including bus scan. A
non zero return value indicates that pci_legacy_init needs to be
called either because the selected function failed or wants the
generic bus scan in pci_legacy_init to happen (e.g. visws).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <43F901BD926A4E43B106BF17856F07559FB80CFE@orsmsx508.amr.corp.intel.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 959e548..73b3fe9 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -282,15 +282,11 @@
 {
 	struct pci_dev *dev = NULL;
 
-	if (pcibios_scanned)
-		return 0;
-
 	if (acpi_noirq)
-		return 0;
+		return -ENODEV;
 
 	printk(KERN_INFO "PCI: Using ACPI for IRQ routing\n");
 	acpi_irq_penalty_init();
-	pcibios_scanned++;
 	pcibios_enable_irq = acpi_pci_irq_enable;
 	pcibios_disable_irq = acpi_pci_irq_disable;