PCI / ACPI: Fix build issue in pci_root.c for !CONFIG_PCIEPORTBUS

The compilation of drivers/acpi/pci_root.c fails if
CONFIG_PCIEPORTBUS is unset.  Fix the problem.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9e67dcd..559d028 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -993,8 +993,13 @@
 extern int pci_msi_enabled(void);
 #endif
 
+#ifdef CONFIG_PCIEPORTBUS
 extern bool pcie_ports_disabled;
 extern bool pcie_ports_auto;
+#else
+#define pcie_ports_disabled	true
+#define pcie_ports_auto		false
+#endif
 
 #ifndef CONFIG_PCIEASPM
 static inline int pcie_aspm_enabled(void)