Merge tag 'pci-v3.12-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI fix from Bjorn Helgaas:
"We merged what was intended to be an MMCONFIG cleanup, but in fact,
for systems without _CBA (which is almost everything), it broke
extended config space for domain 0 and it broke all config space for
other domains.

This reverts the change"

* tag 'pci-v3.12-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
Revert "x86/PCI: MMCONFIG: Check earlier for MMCONFIG region at address zero"

arch/x86/pci/mmconfig-shared.c

···
 	if (!(pci_probe & PCI_PROBE_MMCONF) || pci_mmcfg_arch_init_failed)
 		return -ENODEV;
 
-	if (start > end || !addr)
+	if (start > end)
 		return -EINVAL;
 
 	mutex_lock(&pci_mmcfg_lock);
···
 				  cfg->segment, cfg->start_bus, cfg->end_bus);
 		mutex_unlock(&pci_mmcfg_lock);
 		return -EEXIST;
+	}
+
+	if (!addr) {
+		mutex_unlock(&pci_mmcfg_lock);
+		return -EINVAL;
 	}
 
 	rc = -EBUSY;