x86/PCI: Add NumaChip remote PCI support

Add NumaChip-specific PCI access mechanism via MMCONFIG cycles, but
preventing access to AMD Northbridges which shouldn't respond.

Signed-off-by: Daniel J Blueman <daniel@numascale-asia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 46c3bff..17fb8eb 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -374,6 +374,7 @@
 	depends on NUMA
 	depends on SMP
 	depends on X86_X2APIC
+	depends on PCI_MMCONFIG
 	---help---
 	  Adds support for Numascale NumaChip large-SMP systems. Needed to
 	  enable more than ~168 cores.