x86/amd-iommu: Use dev->arch->iommu to store iommu related information

This patch changes IOMMU code to use dev->archdata->iommu to
store information about the alias device and the domain the
device is attached to.
This allows the driver to get rid of the amd_iommu_pd_table
in the future.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/arch/x86/include/asm/device.h b/arch/x86/include/asm/device.h
index cee34e9..029f230 100644
--- a/arch/x86/include/asm/device.h
+++ b/arch/x86/include/asm/device.h
@@ -8,7 +8,7 @@
 #ifdef CONFIG_X86_64
 struct dma_map_ops *dma_ops;
 #endif
-#ifdef CONFIG_DMAR
+#if defined(CONFIG_DMAR) || defined(CONFIG_AMD_IOMMU)
 	void *iommu; /* hook for IOMMU specific extension */
 #endif
 };