iommu/amd: Add initialization routines for AMD interrupt remapping

Add the six routines required to setup interrupt remapping
with the AMD IOMMU. Also put it all together into the AMD
specific irq_remap_ops.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/drivers/iommu/irq_remapping.h b/drivers/iommu/irq_remapping.h
index 624d360..95363ac 100644
--- a/drivers/iommu/irq_remapping.h
+++ b/drivers/iommu/irq_remapping.h
@@ -82,6 +82,7 @@
 };
 
 extern struct irq_remap_ops intel_irq_remap_ops;
+extern struct irq_remap_ops amd_iommu_irq_ops;
 
 #else  /* CONFIG_IRQ_REMAP */