[PATCH] Fix x86-64 compilation without iommu for 2.6.6rc3

Various people hit this in earlier kernels. The x86-64 kernel did not compile 
without CONFIG_IOMMU_GART in various configurations. Just add the missing symbol 
and export it. Also export iommu_merge while I am at it.

arch/x86_64/kernel/pci-gart.c

@@ -618,6 +618,7 @@ EXPORT_SYMBOL(pci_dma_supported);
 EXPORT_SYMBOL(no_iommu);
 EXPORT_SYMBOL(force_iommu); 
 EXPORT_SYMBOL(bad_dma_address);
+EXPORT_SYMBOL(iommu_merge);
 
 static __init unsigned long check_iommu_size(unsigned long aper, u64 aper_size)
 { 

arch/x86_64/kernel/pci-nommu.c

@@ -5,6 +5,10 @@
 #include <asm/proto.h>
 
 int iommu_merge = 0;
+EXPORT_SYMBOL(iommu_merge);
+
+dma_addr_t bad_dma_address;
+EXPORT_SYMBOL(bad_dma_address);
 
 /* 
  * Dummy IO MMU functions