x86, pci: Exclude Moorestown PCI code if CONFIG_X86_MRST=n

If we don't have any Moorestown CPU support compiled in, we don't need
the Moorestown PCI support either.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4B858E89.7040807@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/pci/Makefile b/arch/x86/pci/Makefile
index 4753ebc..56caf2a 100644
--- a/arch/x86/pci/Makefile
+++ b/arch/x86/pci/Makefile
@@ -13,7 +13,9 @@
 
 obj-$(CONFIG_X86_NUMAQ)		+= numaq_32.o
 
-obj-y				+= common.o early.o mrst.o
+obj-$(CONFIG_X86_MRST)		+= mrst.o
+
+obj-y				+= common.o early.o
 obj-y				+= amd_bus.o
 obj-$(CONFIG_X86_64)		+= bus_numa.o