x86/amd-iommu: Fix passthrough mode

The data structure changes to use dev->archdata.iommu field
broke the iommu=pt mode because in this case the
dev->archdata.iommu was left uninitialized. This moves the
inititalization of the devices into the main init function
and fixes the problem.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/arch/x86/include/asm/amd_iommu_proto.h b/arch/x86/include/asm/amd_iommu_proto.h
index 84786fb..2566e26 100644
--- a/arch/x86/include/asm/amd_iommu_proto.h
+++ b/arch/x86/include/asm/amd_iommu_proto.h
@@ -28,7 +28,8 @@
 extern void amd_iommu_flush_all_devices(void);
 extern void amd_iommu_apply_erratum_63(u16 devid);
 extern void amd_iommu_reset_cmd_buffer(struct amd_iommu *iommu);
-
+extern int amd_iommu_init_devices(void);
+extern void amd_iommu_uninit_devices(void);
 #ifndef CONFIG_AMD_IOMMU_STATS
 
 static inline void amd_iommu_stats_init(void) { }